Copyright (c) 2000 Association of Mizar Users
environ vocabulary FINSEQ_1, FUNCT_1, RELAT_1, BOOLE, POLYNOM1, FUNCOP_1, FINSEQ_4, SEQM_3, PBOOLE, ARYTM_3, ARYTM_1, FUNCT_4, CAT_1, ORDINAL1, FINSET_1, TRIANG_1, ORDERS_2, ALGSEQ_1, GROUP_1, REALSET1, VECTSP_1, POLYNOM2, RLVECT_1, LATTICES, NORMSP_1, POLYNOM3, SQUARE_1, FILTER_2, PRE_TOPC, QUOFIELD, GRCAT_1, IDEAL_1, COHSP_1, PRELAMB, MCART_1, ENDALG, SUBSET_1, BINOP_1, VECTSP_2, CARD_1, TARSKI, DTCONSTR, FUNCT_2, GR_CY_1, HILBASIS; notation TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, CQC_SIM1, SEQM_3, PBOOLE, CQC_LANG, RELAT_1, FINSET_1, FUNCT_1, FINSEQ_1, VECTSP_1, DTCONSTR, NORMSP_1, NUMBERS, XCMPLX_0, XREAL_0, NAT_1, RELSET_1, RLVECT_1, FUNCT_2, FUNCT_4, BINOP_1, GR_CY_1, PRE_CIRC, MCART_1, FINSEQOP, FINSEQ_2, FINSEQ_4, CARD_1, POLYNOM1, POLYNOM2, POLYNOM3, STRUCT_0, PRE_TOPC, GROUP_1, ALGSEQ_1, BINARITH, BORSUK_1, VECTSP_2, IDEAL_1, TOPS_2, ENDALG, GRCAT_1, REALSET1, ORDINAL1, MATRLIN, WSIERP_1, TOPREAL1, TRIANG_1, ORDERS_2, QUOFIELD; constructors ORDERS_2, TRIANG_1, WAYBEL_1, TOPREAL1, CQC_SIM1, MONOID_0, PRE_CIRC, FINSEQOP, POLYNOM3, REAL_1, BINARITH, POLYNOM2, ALGSEQ_1, FINSOP_1, GRCAT_1, BORSUK_1, IDEAL_1, TOPS_2, ENDALG, QUOFIELD, RFUNCT_3, WSIERP_1; clusters CARD_5, RELSET_1, FINSET_1, SUBSET_1, VECTSP_2, STRUCT_0, FUNCT_1, XBOOLE_0, FINSEQ_5, POLYNOM1, POLYNOM2, POLYNOM3, FUNCT_7, INT_1, WAYBEL_2, BINOM, ORDINAL1, CARD_1, IDEAL_1, GOBRD13, GCD_1, MONOID_0, VECTSP_1, XREAL_0, MEMBERED, RELAT_1, PRE_CIRC, NUMBERS, ORDINAL2; requirements NUMERALS, REAL, SUBSET, BOOLE, ARITHM; definitions TARSKI, IDEAL_1, ENDALG, GRCAT_1; theorems CQC_SIM1, TARSKI, ZFMISC_1, RLVECT_1, FUNCT_1, FUNCT_2, POLYNOM1, NAT_1, GR_CY_1, REAL_1, AXIOMS, FVSUM_1, FINSEQ_1, FINSEQ_2, FINSEQ_3, POLYNOM3, BINARITH, JORDAN3, FUNCOP_1, ALGSEQ_1, REAL_2, INT_1, FUNCT_7, IDEAL_1, FINSEQ_4, POLYNOM4, GRCAT_1, QUOFIELD, ENDALG, FUNCT_4, RELAT_1, CARD_1, CARD_2, PRE_CIRC, PRE_TOPC, MATRLIN, ALG_1, GROUP_7, JORDAN4, CARD_3, ORDINAL1, PBOOLE, WAYBEL_1, TRIANG_1, ORDERS_2, FINSET_1, FINSEQOP, CQC_LANG, SEQM_3, POLYNOM2, TOPS_2, FINSEQ_5, GROUP_1, CARD_4, FRECHET2, NORMSP_1, SCMFSA_7, AMI_5, XBOOLE_0, XBOOLE_1, RLVECT_2, SQUARE_1, VECTSP_1, XCMPLX_0, XCMPLX_1, ORDINAL2; schemes NAT_1, RECDEF_1, FUNCT_1, FUNCT_2, FINSEQ_2, FUNCT_7; begin :: Preliminaries theorem Th1: for A,B being FinSequence, f being Function st rng A \/ rng B c= dom f ex fA, fB being FinSequence st fA = f*A & fB = f*B & f*(A^B) = fA^fB proof let A,B being FinSequence, f being Function; assume A1: rng A \/ rng B c= dom f; rng A c= rng A \/ rng B by XBOOLE_1:7; then A2: rng A c= dom f by A1,XBOOLE_1:1; then reconsider fA = f*A as FinSequence by FINSEQ_1:20; A3: dom (f*A) = dom A by A2,RELAT_1:46; then A4: len fA = len A by FINSEQ_3:31; rng B c= rng A \/ rng B by XBOOLE_1:7 ; then A5: rng B c= dom f by A1,XBOOLE_1:1; then reconsider fB = f*B as FinSequence by FINSEQ_1:20; A6: dom (f*B) = dom B by A5,RELAT_1:46; then A7: len fB = len B by FINSEQ_3:31; A8: rng (A^B) c= dom f by A1,FINSEQ_1:44; then reconsider fAB = f*(A^B) as FinSequence by FINSEQ_1:20; A9: dom (f*(A^B)) = dom (A^B) by A8,RELAT_1:46; then A10: len fAB = len (A^B) by FINSEQ_3:31 .= len fA + len fB by A4,A7, FINSEQ_1:35 .= len (fA^fB) by FINSEQ_1:35; take fA, fB; now let k be Nat; assume 1 <=k & k <= len fAB; then A11: k in dom fAB by FINSEQ_3:27; per cases; suppose A12: k in dom fA; hence (fA^fB).k = fA.k by FINSEQ_1:def 7 .= f.(A.k) by A12,FUNCT_1:22 .= f.((A^B).k) by A3,A12,FINSEQ_1:def 7 .= fAB.k by A11,FUNCT_1:22; suppose not k in dom fA; then consider n being Nat such that A13: n in dom B & k=len A + n by A3,A9,A11,FINSEQ_1:38; thus fAB.k = f.((A^B).k) by A11,FUNCT_1:22 .= f.(B.n) by A13,FINSEQ_1:def 7 .= fB.n by A6,A13,FUNCT_1:22 .= (fA^fB).k by A4,A6,A13,FINSEQ_1:def 7; end; hence thesis by A10,FINSEQ_1:18; end; theorem Th2: for b being bag of 0 holds decomp b = <* <* {}, {} *> *> proof let b be bag of 0; b in Bags {} by POLYNOM1:def 14; then A1: b = {} by POLYNOM1:55,TARSKI:def 1; EmptyBag {} = {} --> 0 by POLYNOM1:def 15; then dom EmptyBag {} = {} by FUNCOP_1:16; then A2: EmptyBag 0 = {} by RELAT_1:64; then divisors b = <* {} *> by A1,POLYNOM1:71; then A3: len divisors b = 1 by FINSEQ_1:56; A4: dom divisors b = dom decomp b by POLYNOM1:def 19; then A5: len decomp b = 1 by A3,FINSEQ_3:31; 1 in dom decomp b by A3,A4,FINSEQ_3:27; then (decomp b).1=(decomp b)/.1 by FINSEQ_4:def 4.=<* {},{} *>by A1,A2,POLYNOM1:75; hence decomp b = <* <* {}, {} *> *> by A5,FINSEQ_1:57; end; theorem Th3: for i,j being Nat, b being bag of j st i <= j holds (b|i) is Element of Bags i proof let i,j being Nat, b being bag of j; assume A1: i <= j; A2: rng b c= NAT by SEQM_3:def 8; rng (b|i) c= rng b by FUNCT_1:76; then rng (b|i) c= NAT by A2,XBOOLE_1:1; then A3: (b|i) is natural-yielding by SEQM_3:def 8; i c= j proof let x be set; assume x in i; then x in {y where y is Nat : y < i } by AXIOMS:30; then consider x' being Nat such that A4: x'=x & x' < i; x' < j by A1,A4,AXIOMS:22; then x' in {y where y is Nat : y < j }; hence x in j by A4,AXIOMS:30; end; then i c= dom b by PBOOLE:def 3; then dom (b|i)=i by RELAT_1:91; then (b|i) is ManySortedSet of i by PBOOLE:def 3; hence (b|i) is Element of Bags i by A3,POLYNOM1:def 14; end; theorem Th4: for i, j being set, b1, b2 being bag of j, b1',b2' being bag of i st b1' = (b1|i) & b2' = (b2|i) & b1 divides b2 holds b1' divides b2' proof let i,j be set, b1,b2 be bag of j, b1',b2' be bag of i; assume A1: b1'=(b1|i) & b2'=(b2|i) & b1 divides b2; now let k be set; A2: dom b1' = i by PBOOLE:def 3 .= dom b2' by PBOOLE:def 3; per cases; suppose A3: not k in dom b1'; then b1'.k = {} by FUNCT_1:def 4 .= b2'.k by A2,A3,FUNCT_1:def 4; hence b1'.k <= b2'.k; suppose A4: k in dom b1'; then A5: b1'.k = b1.k by A1,FUNCT_1:70; b2'.k = b2.k by A1,A2,A4,FUNCT_1:70; hence b1'.k <= b2'.k by A1,A5,POLYNOM1:def 13; end; hence b1' divides b2' by POLYNOM1:def 13; end; theorem Th5: for i,j be set, b1, b2 being bag of j, b1', b2' being bag of i st b1'=(b1|i) & b2'=(b2|i) holds (b1-' b2)|i = b1'-' b2' & (b1+b2)|i = b1'+b2' proof let i,j be set, b1, b2 being bag of j, b1', b2' being bag of i; assume A1: b1'=(b1|i) & b2'=(b2|i); dom (b1 -' b2) = j by PBOOLE:def 3; then A2: dom ((b1 -' b2)|i) = j /\ i by RELAT_1:90; dom b1 = j by PBOOLE:def 3 ; then A3: dom (b1|i) = j /\ i by RELAT_1:90; dom b2 = j by PBOOLE:def 3; then A4: dom (b2|i) = j /\ i by RELAT_1:90; A5: dom (b1' -' b2') = i by PBOOLE:def 3 .= j /\ i by A1,A3,PBOOLE:def 3; now let x be set; assume A6: x in j /\ i; hence ((b1 -' b2)|i).x = (b1 -' b2).x by A2,FUNCT_1:70 .= b1.x -' b2.x by POLYNOM1:def 6 .= b1'.x -' b2.x by A1,A3,A6,FUNCT_1:70 .= b1'.x -' b2'.x by A1,A4,A6,FUNCT_1:70 .= (b1' -' b2').x by POLYNOM1:def 6; end; hence (b1 -' b2)|i = b1' -' b2' by A2,A5,FUNCT_1:9; dom (b1 + b2) = j by PBOOLE:def 3; then A7: dom ((b1 + b2)|i) = j /\ i by RELAT_1:90; A8: dom (b1' + b2') = i by PBOOLE:def 3 .= j /\ i by A1,A3,PBOOLE:def 3; now let x be set; assume A9: x in j /\ i; hence ((b1 + b2)|i).x = (b1 + b2).x by A7,FUNCT_1:70 .= b1.x + b2.x by POLYNOM1:def 5 .= b1'.x + b2.x by A1,A3,A9,FUNCT_1:70 .= b1'.x + b2'.x by A1,A4,A9,FUNCT_1:70 .= (b1' + b2').x by POLYNOM1:def 5; end; hence (b1 + b2)|i = b1'+b2' by A7,A8,FUNCT_1:9; end; definition let n,k be Nat, b be bag of n; func b bag_extend k -> Element of Bags (n+1) means :Def1: it|n = b & it.n = k; existence proof set b1 = b +* (n .--> k); rng b1 c= NAT proof let y be set; assume y in rng b1; then consider x being set such that A1: x in dom b1 & y = b1.x by FUNCT_1:def 5; A2: x in dom b \/ dom (n .--> k) by A1,FUNCT_4:def 1; per cases; suppose A3: x in dom (n .--> k); then x in {n} by CQC_LANG:5; then x=n by TARSKI:def 1; then y = (n .--> k).n by A1,A2,A3,FUNCT_4:def 1 .= k by CQC_LANG:6; hence y in NAT; suppose not x in dom (n .--> k); then y = b.x by A1,A2,FUNCT_4:def 1; hence y in NAT; end; then A4: b1 is natural-yielding by SEQM_3:def 8; A5: dom b1 = dom b \/ dom (n .--> k) by FUNCT_4:def 1 .= dom b \/ {n} by CQC_LANG:5 .= n \/ {n} by PBOOLE:def 3 .= succ n by ORDINAL1:def 1 .= n+1 by CARD_1:52; then b1 is ManySortedSet of n+1 by PBOOLE:def 3; then reconsider b1 as Element of Bags (n+1) by A4,POLYNOM1:def 14; take b1; A6: dom (b1|n) = (n+1) /\ n by A5,FUNCT_1:68 .= succ n /\ n by CARD_1:52 .= (n \/ {n}) /\ n by ORDINAL1:def 1 .= n by XBOOLE_1:21; A7: dom b = n by PBOOLE:def 3; now let x be set; assume A8: x in n; then A9: x in dom b \/ dom (n .--> k) by A7,XBOOLE_0:def 2; A10: now assume x in dom (n .--> k); then x in {n} by CQC_LANG:5; then x = n by TARSKI:def 1; hence contradiction by A8; end; thus (b1|n).x=b1.x by A6,A8,FUNCT_1:68 .= b.x by A9,A10,FUNCT_4:def 1; end; hence b1|n = b by A6,A7,FUNCT_1:9; n in {n} by TARSKI:def 1; then A11: n in dom (n .--> k) by CQC_LANG:5; then n in dom b \/ dom (n .--> k) by XBOOLE_0:def 2; hence b1.n = (n .--> k).n by A11,FUNCT_4:def 1 .= k by CQC_LANG:6; end; uniqueness proof let b1,b2 be Element of Bags (n+1); assume A12: b1|n = b & b1.n = k & b2|n = b & b2.n = k; A13: dom b1 = n+1 by PBOOLE:def 3; A14: dom b2 = n+1 by PBOOLE:def 3; now let x be set; assume A15: x in n+1; then x in succ n by CARD_1:52; then A16: x in n \/ {n} by ORDINAL1:def 1; per cases; suppose x in {n}; then x = n by TARSKI:def 1; hence b1.x = b2.x by A12; suppose not x in {n}; then x in n by A16,XBOOLE_0:def 2; then x in (n+1) /\ n by A15,XBOOLE_0:def 3; then A17: x in dom b by A12,A13,FUNCT_1:68; hence b1.x = b.x by A12,FUNCT_1:70 .= b2.x by A12,A17,FUNCT_1:70; end; hence b1 = b2 by A13,A14,FUNCT_1:9; end; end; theorem Th6: for n being Nat holds EmptyBag (n+1) = (EmptyBag n) bag_extend 0 proof let n being Nat; A1: dom (EmptyBag (n+1)) = n+1 by PBOOLE:def 3; A2: dom ((EmptyBag n) bag_extend 0) = n+1 by PBOOLE:def 3; now let x be set; assume x in n+1; then x in succ n by CARD_1:52; then A3: x in n \/ {n} by ORDINAL1:def 1; per cases by A3,XBOOLE_0:def 2; suppose A4: x in n; thus (EmptyBag(n+1)).x = 0 by POLYNOM1:56 .= (EmptyBag n).x by POLYNOM1:56 .= (((EmptyBag n) bag_extend 0)|n).x by Def1 .= ((EmptyBag n) bag_extend 0).x by A4,FUNCT_1:72; suppose A5: x in {n}; thus (EmptyBag(n+1)).x = 0 by POLYNOM1:56 .= ((EmptyBag n) bag_extend 0).n by Def1 .= ((EmptyBag n) bag_extend 0).x by A5,TARSKI:def 1; end; hence EmptyBag (n+1) = (EmptyBag n) bag_extend 0 by A1,A2,FUNCT_1:9; end; theorem Th7: for n be Ordinal, b, b1 be bag of n holds b1 in rng divisors b iff b1 divides b proof let n be Ordinal, b, b1 be bag of n; consider S being non empty finite Subset of Bags n such that A1: divisors b = SgmX(BagOrder n, S) & for p being bag of n holds p in S iff p divides b by POLYNOM1:def 18; field (BagOrder n) = Bags n by ORDERS_2:2; then BagOrder n linearly_orders Bags n by ORDERS_2:35; then A2: BagOrder n linearly_orders S by ORDERS_2:36; hereby assume b1 in rng divisors b; then b1 in S by A1,A2,TRIANG_1:def 2 ; hence b1 divides b by A1; end; assume b1 divides b; then b1 in S by A1; hence b1 in rng divisors b by A1,A2,TRIANG_1:def 2; end; definition let X be set, x be Element of X; func UnitBag x -> Element of Bags X equals :Def2: (EmptyBag X)+*(x, 1); coherence by POLYNOM1:def 14; end; theorem Th8: for X being non empty set, x being Element of X holds support UnitBag x = {x} proof let X be non empty set, x be Element of X; now let a be set; hereby assume a in support UnitBag x; then A1: a in support ((EmptyBag X)+*(x, 1)) by Def2; now assume a <> x; then ((EmptyBag X)+*(x, 1)).a = (EmptyBag X).a by FUNCT_7:34 .= 0 by POLYNOM1:56; hence contradiction by A1,POLYNOM1:def 7; end; hence a in {x} by TARSKI:def 1; end; assume a in {x}; then A2: a = x by TARSKI:def 1; EmptyBag X = X --> 0 by POLYNOM1:def 15 ; then A3: dom (EmptyBag X) = X by FUNCOP_1:19; (UnitBag x).a = ((EmptyBag X)+*(x, 1)).a by Def2 .= 1 by A2,A3,FUNCT_7:33; hence a in support UnitBag x by POLYNOM1:def 7; end; hence support UnitBag x = {x} by TARSKI:2; end; theorem Th9: for X being non empty set, x being Element of X holds (UnitBag x).x = 1 & for y being Element of X st x <> y holds (UnitBag x).y = 0 proof let X be non empty set, x be Element of X; A1: dom (X -->0) = X by FUNCOP_1:19; thus (UnitBag x).x = ((EmptyBag X)+*(x, 1)).x by Def2 .= ((X --> 0)+*(x, 1)).x by POLYNOM1:def 15 .= 1 by A1,FUNCT_7:33; let y be Element of X such that A2: x <> y; thus (UnitBag x).y = ((EmptyBag X)+*(x, 1)).y by Def2 .= (EmptyBag X).y by A2,FUNCT_7:34 .= 0 by POLYNOM1:56; end; theorem Th10: for X being non empty set, x1, x2 being Element of X st UnitBag x1 = UnitBag x2 holds x1 = x2 proof let X be non empty set, x1, x2 be Element of X such that A1: UnitBag x1 = UnitBag x2 and A2: x1 <> x2; 1 = (UnitBag x2).x1 by A1,Th9 .= 0 by A2,Th9; hence contradiction; end; theorem Th11: for X being non empty Ordinal, x be Element of X, L being unital non trivial (non empty doubleLoopStr), e being Function of X, L holds eval(UnitBag x, e) = e.x proof let X be non empty Ordinal, x be Element of X, L be unital non trivial (non empty doubleLoopStr), e be Function of X, L; reconsider edx = e.x as Element of L; support UnitBag x = {x} by Th8; hence eval(UnitBag x, e) = power(L).(e.x, (UnitBag x).x) by POLYNOM2:17 .= power(L).(e.x, 0+1) by Th9 .= power(L).(edx, 0) * (edx) by GROUP_1:def 7 .= 1.L * (edx) by GROUP_1:def 7 .= e.x by GROUP_1:def 4; end; definition let X be set, x be Element of X, L be unital (non empty multLoopStr_0); func 1_1(x,L) -> Series of X, L equals :Def3: 0_(X,L)+*(UnitBag x,1.L); coherence; end; theorem Th12: for X being set, L being unital non trivial (non empty doubleLoopStr), x be Element of X holds 1_1(x,L).UnitBag x = 1.L & for b being bag of X st b <> UnitBag x holds 1_1(x,L).b = 0.L proof let X be set, L be unital non trivial (non empty doubleLoopStr), x be Element of X; A1: dom (0_(X,L)) = dom ((Bags X) --> 0.L) by POLYNOM1:def 24 .= Bags X by FUNCOP_1:19; thus 1_1(x,L).UnitBag x = (0_(X,L)+*(UnitBag x,1.L)).UnitBag x by Def3 .= 1.L by A1,FUNCT_7:33; let b be bag of X; assume A2: b <> UnitBag x; thus 1_1(x,L).b = (0_(X,L)+*(UnitBag x,1.L)).b by Def3 .= (0_(X,L)).b by A2,FUNCT_7:34 .= 0.L by POLYNOM1:81; end; theorem Th13: for X being set, x being Element of X, L being add-associative right_zeroed right_complementable unital right-distributive non trivial (non empty doubleLoopStr) holds Support 1_1(x,L) = {UnitBag x} proof let X be set, x be Element of X, L be add-associative right_zeroed right_complementable unital right-distributive non trivial (non empty doubleLoopStr); now let a be set; hereby assume A1: a in Support 1_1(x,L); then reconsider b = a as Element of Bags X; now assume A2: a <> UnitBag x; 1_1(x,L).b = (0_(X,L)+*(UnitBag x,1.L)).b by Def3 .= (0_(X,L)).b by A2,FUNCT_7:34 .= 0.L by POLYNOM1:81; hence contradiction by A1,POLYNOM1:def 9; end; hence a in {UnitBag x} by TARSKI:def 1; end; assume a in {UnitBag x}; then A3: a = UnitBag x by TARSKI:def 1; then 1_1(x,L).a = 1.L by Th12; then 1_1(x,L).a <> 0.L by POLYNOM1:27; hence a in Support 1_1(x,L) by A3,POLYNOM1:def 9; end; hence Support 1_1(x,L) = {UnitBag x} by TARSKI:2; end; definition let X be Ordinal, x be Element of X, L be add-associative right_zeroed right_complementable unital right-distributive non trivial (non empty doubleLoopStr); cluster 1_1(x,L) -> finite-Support; coherence proof Support 1_1(x,L) = {UnitBag x} by Th13; hence thesis by POLYNOM1:def 10; end; end; theorem Th14: for L being add-associative right_zeroed right_complementable unital right-distributive non trivial (non empty doubleLoopStr), X being non empty set, x1, x2 being Element of X st 1_1(x1,L) = 1_1(x2,L) holds x1 = x2 proof let L be add-associative right_zeroed right_complementable unital right-distributive non trivial (non empty doubleLoopStr), X be non empty set, x1, x2 be Element of X such that A1: 1_1(x1,L) = 1_1(x2,L) and A2: x1 <> x2; A3: UnitBag x1 <> UnitBag x2 by A2,Th10; 1.L = 1_1(x2,L).UnitBag x1 by A1,Th12 .= 0.L by A3,Th12; hence contradiction by POLYNOM1:27; end; theorem Th15: for L being add-associative right_zeroed right_complementable distributive (non empty doubleLoopStr), x being Element of Polynom-Ring L, p be sequence of L st x = p holds -x = -p proof let L be add-associative right_zeroed right_complementable distributive (non empty doubleLoopStr), x being Element of Polynom-Ring L, p be sequence of L; assume A1: x = p; reconsider x'=x as Polynomial of L by POLYNOM3:def 12; A2: dom 0_.L = NAT by FUNCT_2:def 1; A3: dom (p-p) = NAT by FUNCT_2:def 1; now let i be set; assume A4: i in NAT; then reconsider i'=i as Nat; thus (p-p).i = p.i' - p.i' by POLYNOM3:27 .= 0.L by RLVECT_1:28 .= (0_.L).i by A4,POLYNOM3:28; end; then p-p = 0_.L by A2,A3,FUNCT_1:9; then A5: x'+-x' = 0_.L by A1,POLYNOM3:def 8; reconsider mx=-x' as Element of Polynom-Ring L by POLYNOM3:def 12; x+mx = x'+-x' by POLYNOM3:def 12 .=0.(Polynom-Ring L) by A5,POLYNOM3:def 12 ; then x = -mx by RLVECT_1:19; hence thesis by A1,RLVECT_1:30; end; theorem Th16: for L being add-associative right_zeroed right_complementable distributive (non empty doubleLoopStr), x, y being Element of Polynom-Ring L, p, q be sequence of L st x = p & y = q holds x-y = p-q proof let L being add-associative right_zeroed right_complementable distributive (non empty doubleLoopStr), x,y being Element of Polynom-Ring L, p,q be sequence of L; assume A1: x = p & y = q; then A2: -y = -q by Th15; thus x - y = x + (-y) by RLVECT_1:def 11 .= p + (-q) by A1,A2,POLYNOM3:def 12 .= p - q by POLYNOM3:def 8; end; definition let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr); let I be non empty Subset of Polynom-Ring L; func minlen(I) -> non empty Subset of I equals :Def4: { x where x is Element of I : for x',y' being Polynomial of L st x'=x & y' in I holds len x' <= len y' }; coherence proof set u = { x where x is Element of I : for x',y' being Polynomial of L st x'=x & y' in I holds len x' <= len y' }; A1: u c= I proof let x be set; assume x in u; then consider x'' being Element of I such that A2: x''=x & for x',y' being Polynomial of L st x'=x'' & y' in I holds len x' <= len y'; thus x in I by A2; end; defpred P[Element of I,Nat] means for p being Polynomial of L st $1=p holds $2 = len p; A3: now let x be Element of I; reconsider x'=x as Polynomial of L by POLYNOM3:def 12; for p be Polynomial of L st x=p holds len x' = len p; hence ex y being Nat st P[x,y]; end; consider f being Function of I,NAT such that A4: for x being Element of I holds P[x,f.x] from FuncExD(A3); I c= I; then reconsider I'=I as non empty Subset of I; min (f.:I') in f.:I by CQC_SIM1:def 8; then consider x being set such that A5: x in dom f & x in I & min (f.:I') = f.x by FUNCT_1:def 12; reconsider x as Element of I by A5; now let x',y' being Polynomial of L; assume A6: x'=x & y' in I; dom f = I by FUNCT_2:def 1; then f.y' in f.:I by A6,FUNCT_1:def 12 ; then f.x <= f.y' by A5,CQC_SIM1:def 8; then len x' <= f.y' by A4,A6 ; hence len x' <= len y' by A4,A6; end; then x in u; hence u is non empty Subset of I by A1; end; end; theorem Th17: for L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), I be non empty Subset of Polynom-Ring L, i1, i2 be Polynomial of L st i1 in minlen(I) & i2 in I holds i1 in I & len i1 <= len i2 proof let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), I be non empty Subset of Polynom-Ring L, i1, i2 be Polynomial of L; assume A1: i1 in minlen(I) & i2 in I; then i1 in { x where x is Element of I : for x',y' being Polynomial of L st x'=x & y' in I holds len x' <= len y' } by Def4; then consider i1' being Element of I such that A2: i1'=i1 & for x',y' being Polynomial of L st x'=i1' & y' in I holds len x' <= len y'; thus i1 in I & len i1 <= len i2 by A1,A2; end; definition let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n be Nat, a be Element of L; func monomial(a,n) -> Polynomial of L means :Def5: for x being Nat holds (x = n implies it.x = a) & (x <> n implies it.x = 0.L); existence proof reconsider x = 0_.(L)+*(n,a) as sequence of L by NORMSP_1:def 3; now let i be Nat; assume i >= n+1; then i > n by NAT_1:38; hence x.i = (0_.(L)).i by FUNCT_7:34 .= (NAT --> 0.L).i by POLYNOM3:def 9 .= 0.L by FUNCOP_1:13; end; then reconsider x as Polynomial of L by ALGSEQ_1:def 2; now let i be Nat; thus i = n implies x.i = a proof assume A1: i = n; dom 0_.(L) = NAT by FUNCT_2:def 1; hence x.i = a by A1,FUNCT_7:33; end; thus i <> n implies x.i = 0.L proof assume i <> n; hence x.i = (0_.L).i by FUNCT_7:34 .= (NAT --> 0.L).i by POLYNOM3:def 9 .= 0.L by FUNCOP_1:13; end; end; hence thesis; end; uniqueness proof let u,v be Polynomial of L such that A2: for x being Nat holds (x=n implies u.x=a) & (x<>n implies u.x = 0.L) and A3: for x being Nat holds (x=n implies v.x=a) & (x<>n implies v.x = 0.L); A4: dom u = NAT by FUNCT_2:def 1; A5: dom v = NAT by FUNCT_2:def 1; now let x be set; assume A6: x in NAT; per cases; suppose A7: x = n; hence u.x = a by A2 .= v.x by A3,A7; suppose A8: x <> n; hence u.x = 0.L by A2,A6 .= v.x by A3,A6,A8; end; hence u = v by A4,A5,FUNCT_1:9; end; end; theorem Th18: for L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n be Nat, a be Element of L holds (a <> 0.L implies len monomial(a,n) = n+1) & (a = 0.L implies len monomial(a,n) = 0) & len monomial (a,n) <= n+1 proof let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n be Nat, a be Element of L; A1: now assume a <> 0.L; then monomial(a,n).n <> 0.L by Def5; then len monomial(a,n) > n by ALGSEQ_1:22; then A2: len monomial(a,n) >= n+1 by NAT_1:38; now let i be Nat; assume i >= n+1; then i > n by NAT_1:38; hence monomial(a,n).i = 0.L by Def5; end; then n+1 is_at_least_length_of monomial(a,n) by ALGSEQ_1:def 3; then len monomial(a,n) <= n+1 by ALGSEQ_1:def 4; hence len monomial(a,n) = n+1 by A2,AXIOMS:21; end; now assume A3: a = 0.L; now let i be Nat; assume i >= 0; per cases; suppose i = n; hence monomial(a,n).i = 0.L by A3,Def5; suppose i<>n; hence monomial(a,n).i = 0.L by Def5; end; then 0 is_at_least_length_of monomial(a,n) by ALGSEQ_1:def 3; then len monomial(a,n)<=0 by ALGSEQ_1:def 4; hence len monomial(a,n) = 0 by NAT_1:18; end; hence thesis by A1,NAT_1:18; end; theorem Th19: for L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n, x be Nat, a be Element of L, p be Polynomial of L holds (monomial(a,n)*'p).(x+n) = a * (p.x) proof let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n,x be Nat, a be Element of L, p be Polynomial of L; consider r being FinSequence of the carrier of L such that A1: len r = x+n+1 & (monomial(a,n)*'p).(x+n) = Sum r & for k be Nat st k in dom r holds r.k = monomial(a,n).(k-'1) * p.(x+n+1-'k) by POLYNOM3:def 11; len r = n+(1+x) by A1,XCMPLX_1:1; then consider b,c being FinSequence of the carrier of L such that A2: len b = n & len c = 1+x & r = b^c by FINSEQ_2:26; consider d,e being FinSequence of the carrier of L such that A3: len d = 1 & len e = x & c = d^e by A2,FINSEQ_2:26; now let i be Nat; assume A4: i in dom b; then A5: 1 <= i & i <= n by A2,FINSEQ_3:27; then A6: i-'1 = i-1 by SCMFSA_7:3; A7: i - 1 < i by INT_1:26; A8: dom b c= dom r by A2,FINSEQ_1:39; thus b.i = r.i by A2,A4,FINSEQ_1:def 7 .= monomial(a,n).(i-'1)*p.(x+n+1-'i) by A1,A4,A8 .= 0.L * p.(x+n+1-'i) by A5,A6,A7,Def5 .= 0.L by VECTSP_1:39; end; then A9: Sum b = 0.L by POLYNOM3:1; A10: 1 in dom d by A3,FINSEQ_3:27; A11: dom d c= dom c by A3,FINSEQ_1:39; then A12: n+1 in dom r by A2,A10,FINSEQ_1:41; d.1 = c.1 by A3,A10,FINSEQ_1:def 7 .= r.(n+1) by A2,A10,A11,FINSEQ_1:def 7 .= monomial(a,n).(n+1-'1)*p.(x+n+1-'(n+1)) by A1,A12 .= monomial(a,n).n*p.(x+n+1-'(n+1)) by BINARITH:39 .= monomial(a,n).n*p.(x+(n+1)-'(n+1)) by XCMPLX_1:1 .= monomial(a,n).n*p.x by BINARITH:39 .= a*p.x by Def5; then d = <* a*p.x *> by A3,FINSEQ_1:57; then A13: Sum d = a * (p.x) by RLVECT_1:61; now let i be Nat; assume A14: i in dom e; then A15: 1+i in dom c by A3,FINSEQ_1:41; then A16: n+(1+i) in dom r by A2,FINSEQ_1:41; i >= 1 by A14,FINSEQ_3:27 ; then n+i >= n+1 by AXIOMS:24; then A17: n+i > n by NAT_1:38; A18: n+(1+i) -' 1 = n+i+1 -' 1 by XCMPLX_1:1 .= n+i by BINARITH:39; thus e.i = c.(1+i) by A3,A14,FINSEQ_1:def 7 .= r.(n+(1+i)) by A2,A15,FINSEQ_1:def 7 .= monomial(a,n).(n+(1+i)-'1)*p.(x+n+1-'(n+(1+i))) by A1,A16 .= 0.L * p.(x+n+1-'(n+(1+i))) by A17,A18,Def5 .= 0.L by VECTSP_1:39; end; then Sum e = 0.L by POLYNOM3:1; then Sum c = a * (p.x) + 0.L by A3,A13,RLVECT_1:58 .= a * (p.x) by RLVECT_1 :10; hence (monomial(a,n)*'p).(x+n) = 0.L + a * (p.x) by A1,A2,A9,RLVECT_1:58 .= a * (p.x) by RLVECT_1:10; end; theorem Th20: for L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n, x be Nat, a be Element of L, p be Polynomial of L holds (p*'monomial(a,n)).(x+n) = (p.x) * a proof let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), n,x be Nat, a be Element of L, p be Polynomial of L; consider r being FinSequence of the carrier of L such that A1: len r = x+n+1 & (p*'monomial(a,n)).(x+n) = Sum r & for k be Nat st k in dom r holds r.k = p.(k-'1) * monomial(a,n).(x+n+1-'k) by POLYNOM3:def 11; len r = x+(n+1) by A1,XCMPLX_1:1; then consider b,c being FinSequence of the carrier of L such that A2: len b = x & len c = n+1 & r = b^c by FINSEQ_2:26; consider d,e being FinSequence of the carrier of L such that A3: len d = 1 & len e = n & c = d^e by A2,FINSEQ_2:26; now let i be Nat; assume A4: i in dom b; then 1 <= i & i <= x by A2,FINSEQ_3:27; then i+n <= x+n by AXIOMS:24; then i+n < x+n+1 by NAT_1:38; then A5: n < x+n+1-i by REAL_1:86; then x+n+1-i > 0 by NAT_1:18; then A6: x+n+1-i = x+n+1-'i by BINARITH:def 3; A7: dom b c= dom r by A2,FINSEQ_1:39; thus b.i = r.i by A2,A4,FINSEQ_1:def 7 .= p.(i-'1)*monomial(a,n).(x+n+1-'i) by A1,A4,A7 .= p.(i-'1)*0.L by A5,A6,Def5 .= 0.L by VECTSP_1:36; end; then A8: Sum b = 0.L by POLYNOM3:1; A9: 1 in dom d by A3,FINSEQ_3:27; A10: dom d c= dom c by A3,FINSEQ_1:39; then A11: x+1 in dom r by A2,A9,FINSEQ_1:41; d.1 = c.1 by A3,A9,FINSEQ_1:def 7 .= r.(x+1) by A2,A9,A10,FINSEQ_1:def 7 .= p.(x+1-'1)*monomial(a,n).(x+n+1-'(x+1)) by A1,A11 .= p.x*monomial(a,n).(x+n+1-'(x+1)) by BINARITH:39 .= p.x*monomial(a,n).(n+(x+1)-'(x+1)) by XCMPLX_1:1 .= p.x*monomial(a,n).n by BINARITH:39 .= p.x*a by Def5; then d = <* p.x*a *> by A3,FINSEQ_1:57; then A12: Sum d = p.x*a by RLVECT_1:61; now let i be Nat; assume A13: i in dom e; then A14: 1+i in dom c by A3,FINSEQ_1:41; then A15: x+(1+i) in dom r by A2,FINSEQ_1:41; A16: 1 <= i & i <= n by A3,A13,FINSEQ_3:27; then x+i <= x+n by AXIOMS:24; then x+i+1<=x+n+1 by AXIOMS:24; then x+(i+1)<=x+n+1 by XCMPLX_1:1; then A17: x+n+1 -' (x+(1+i)) = x+n+1 - (x+(1+i)) by SCMFSA_7:3; A18: x+n+1 - (x+(1+i)) = x+n+1 - x - (1+i) by XCMPLX_1:36 .= x+(n+1)-x - (1+i) by XCMPLX_1:1 .= x-x+(n+1)-(1+i) by XCMPLX_1:29 .= 0+(n+1)-(1+i) by XCMPLX_1:14 .= n-i by XCMPLX_1:32; A19: n-i <= n-1 by A16,REAL_1:92; A20: n > n-1 by INT_1:26; thus e.i = c.(1+i) by A3,A13,FINSEQ_1:def 7 .= r.(x+(1+i)) by A2,A14,FINSEQ_1:def 7 .= p.(x+(1+i)-'1)*monomial(a,n).(x+n+1-'(x+(1+i))) by A1,A15 .= p.(x+(1+i)-'1)*0.L by A17,A18,A19,A20,Def5 .= 0.L by VECTSP_1:36; end; then Sum e = 0.L by POLYNOM3:1; then Sum c = (p.x)*a + 0.L by A3,A12,RLVECT_1:58 .= (p.x)*a by RLVECT_1:10 ; hence (p*'monomial(a,n)).(x+n) = 0.L + (p.x)*a by A1,A2,A8,RLVECT_1:58 .= (p.x)*a by RLVECT_1:10; end; theorem Th21: for L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), p, q be Polynomial of L holds len (p*'q) <= (len p)+(len q)-'1 proof let L be right_zeroed add-associative right_complementable unital distributive (non empty doubleLoopStr), p,q be Polynomial of L; now let i be Nat; consider r be FinSequence of the carrier of L such that A1: len r = i+1 and A2: (p*'q).i = Sum r and A3: for k be Nat st k in dom r holds r.k=p.(k-'1) * q.(i+1-'k) by POLYNOM3:def 11; assume A4: i >= len p + len q -' 1; len p + len q -' 1 >= len p + len q - 1 by JORDAN3:3; then i >= len p + len q - 1 by A4,AXIOMS:22; then i >= len p + (len q - 1) by XCMPLX_1:29; then len p <= i - (len q - 1) by REAL_1:84; then len p <= i - len q + 1 by XCMPLX_1:37; then -len p >= -(i - len q + 1) by REAL_1:50; then -len p >= -(i - (len q -1)) by XCMPLX_1:37; then A5: -len p >= len q -1 -i by XCMPLX_1:143; now let k be Nat; assume A6: k in dom r; then A7: r.k = p.(k-'1) * q.(i+1-'k) by A3; k in Seg len r by A6,FINSEQ_1:def 3; then A8: 1 <= k & k <= i+1 by A1,FINSEQ_1:3; then A9: i+1-k >= 0 by SQUARE_1:12; A10: k-1 >= 0 by A8,SQUARE_1:12; per cases; suppose k-'1 < len p; then k-1 < len p by A10,BINARITH:def 3; then -(k-1) > -len p by REAL_1:50; then 1-k > -len p by XCMPLX_1:143; then 1-k > len q - 1 - i by A5,AXIOMS:22; then i+(1-k)>len q - 1 by REAL_1:84; then i+1-k>len q - 1 by XCMPLX_1: 29; then i+1-'k > len q -1 by A9,BINARITH:def 3; then i+1-'k >= len q -1 +1 by INT_1:20; then i+1-'k >= len q +1 -1 by XCMPLX_1:29; then i+1-'k >= len q by XCMPLX_1:26; then q.(i+1-'k) = 0.L by ALGSEQ_1:22; hence r.k = 0.L by A7,VECTSP_1:36; suppose k-'1 >= len p; then p.(k-'1) = 0.L by ALGSEQ_1:22; hence r.k = 0.L by A7,VECTSP_1:39; end; hence (p*'q).i = 0.L by A2,POLYNOM3:1; end; then len p + len q -' 1 is_at_least_length_of p*'q by ALGSEQ_1:def 3; hence thesis by ALGSEQ_1:def 4; end; begin :: On Ring isomorphism theorem Th22: for R,S being non empty doubleLoopStr, I being Ideal of R, P being map of R,S st P is RingIsomorphism holds P.:I is Ideal of S proof let R,S being non empty doubleLoopStr, I being Ideal of R, P being map of R,S; assume A1: P is RingIsomorphism; set Q = P.:I; A2: now let x, y be Element of S; assume A3: x in Q & y in Q; then consider x' being set such that A4: x' in the carrier of R & x' in I & x = P.x' by FUNCT_2:115; consider y' being set such that A5: y' in the carrier of R & y' in I & y = P.y' by A3,FUNCT_2:115; reconsider x',y' as Element of R by A4,A5; A6: x'+y' in I by A4,A5,IDEAL_1:def 1; P is RingMonomorphism RingEpimorphism by A1,QUOFIELD:def 24; then P is RingHomomorphism by QUOFIELD:def 22; then P is additive by QUOFIELD:def 21; then x+y = P.(x'+y') by A4,A5,GRCAT_1:def 13; hence x+y in Q by A6,FUNCT_2:43; end; A7: now let p, x be Element of S; assume x in Q; then consider x' being set such that A8: x' in the carrier of R & x' in I & x = P.x' by FUNCT_2:115; reconsider x' as Element of R by A8; A9: P is RingMonomorphism RingEpimorphism by A1,QUOFIELD:def 24; then rng P = the carrier of S by QUOFIELD:def 22; then consider p' being set such that A10: p' in dom P & p = P.p' by FUNCT_1:def 5; reconsider p' as Element of R by A10; A11: p'*x' in I by A8,IDEAL_1:def 2; P is RingHomomorphism by A9,QUOFIELD:def 22; then P is multiplicative by QUOFIELD:def 21; then p*x = P.(p'*x') by A8,A10,ENDALG:def 7; hence p*x in Q by A11,FUNCT_2:43; end; now let p, x be Element of S; assume x in Q; then consider x' being set such that A12: x' in the carrier of R & x' in I & x = P.x' by FUNCT_2:115; reconsider x' as Element of R by A12; A13: P is RingMonomorphism RingEpimorphism by A1,QUOFIELD:def 24; then rng P = the carrier of S by QUOFIELD:def 22; then consider p' being set such that A14: p' in dom P & p = P.p' by FUNCT_1:def 5; reconsider p' as Element of R by A14; A15: x'*p' in I by A12,IDEAL_1:def 3; P is RingHomomorphism by A13,QUOFIELD:def 22; then P is multiplicative by QUOFIELD:def 21; then x*p = P.(x'*p') by A12,A14,ENDALG:def 7; hence x*p in Q by A15,FUNCT_2:43; end; hence Q is Ideal of S by A2,A7,IDEAL_1:def 1,def 2,def 3; end; theorem Th23: :: from quofield for R,S being add-associative right_zeroed right_complementable (non empty doubleLoopStr), f being map of R, S st f is RingHomomorphism holds f.(0.R) = 0.S proof let R,S be add-associative right_zeroed right_complementable (non empty doubleLoopStr); let f be map of R, S; assume f is RingHomomorphism; then A1: f is additive by QUOFIELD:def 21; f.(0.R)=f.(0.R+0.R) by RLVECT_1:10 .= f.(0.R)+f.(0.R) by A1,GRCAT_1:def 13; then 0.S = (f.(0.R)+f.(0.R))+(-f.(0.R)) by RLVECT_1:def 10 .= f.(0.R) + (f.(0.R) + (-f.(0.R))) by RLVECT_1:def 6 .= f.(0.R) + 0.S by RLVECT_1:def 10 .= f.(0.R) by RLVECT_1:10; hence thesis; end; theorem Th24: for R, S being add-associative right_zeroed right_complementable (non empty doubleLoopStr), F being non empty Subset of R, G being non empty Subset of S, P being map of R, S, lc being LinearCombination of F, LC being LinearCombination of G, E being FinSequence of [:the carrier of R, the carrier of R, the carrier of R:] st P is RingHomomorphism & len lc = len LC & E represents lc & (for i being set st i in dom LC holds LC.i = (P.(E/.i)`1)*(P.(E/.i)`2)*(P.(E/.i)`3)) holds P.(Sum lc) = Sum LC proof let R, S be add-associative right_zeroed right_complementable (non empty doubleLoopStr), F be non empty Subset of R, G be non empty Subset of S, P be map of R,S, lc be LinearCombination of F, LC be LinearCombination of G, E be FinSequence of [:the carrier of R, the carrier of R, the carrier of R:] such that A1: P is RingHomomorphism and A2: len lc = len LC and A3: E represents lc and A4: for i being set st i in dom LC holds LC.i = (P.(E/.i)`1)*(P.(E/.i)`2)*(P.(E/.i)`3); A5: dom lc = dom LC by A2,FINSEQ_3:31; A6: P is additive multiplicative by A1,QUOFIELD:def 21; defpred P[Nat] means for lc' being LinearCombination of F, LC' being LinearCombination of G st lc' = lc|Seg $1 & LC' = LC|Seg $1 holds P.(Sum lc') = Sum LC'; A7: P[0] proof let lc' be LinearCombination of F, LC' be LinearCombination of G such that A8: lc' = lc|Seg 0 & LC' = LC|Seg 0; thus P.(Sum lc') = P.(Sum <*>the carrier of R) by A8,FINSEQ_1:4,RELAT_1:110 .= P.(0.R) by RLVECT_1:60 .= 0.S by A1,Th23 .= Sum <*>the carrier of S by RLVECT_1:60 .= Sum LC' by A8,FINSEQ_1:4,RELAT_1:110; end; A9: for k being Nat st P[k] holds P[k+1] proof let k be Nat; assume A10: P[k]; thus P[k+1] proof let lc' be LinearCombination of F, LC' be LinearCombination of G; assume A11: lc' = lc| Seg (k+1) & LC' = LC|Seg (k+1); per cases; suppose A12: len lc < k+1; then A13: len lc <= k by NAT_1:38; A14: lc' = lc by A11,A12,FINSEQ_3:55 .= lc|Seg k by A13,FINSEQ_3:55 ; LC' = LC by A2,A11,A12,FINSEQ_3:55 .= LC|Seg k by A2,A13,FINSEQ_3:55; hence P.(Sum lc') = Sum LC' by A10,A14; suppose A15: len lc >= k+1; 1 <= k+1 by NAT_1:29; then A16: k+1 in dom lc by A15,FINSEQ_3:27; reconsider lck = lc|Seg k as LinearCombination of F by IDEAL_1:41; reconsider LCk = LC|Seg k as LinearCombination of G by IDEAL_1:41; set i = k+1; A17: lc|Seg (k+1) = lck^<*lc.(k+1)*> by A16,FINSEQ_5:11; A18: LC.(k+1) = LC/.(k+1) by A5,A16,FINSEQ_4:def 4; A19: lc.(k+1) = lc/.(k+1) by A16,FINSEQ_4:def 4; hence P.(Sum lc') = P.((Sum lck)+lc/.(k+1)) by A11,A17,FVSUM_1:87 .= P.(Sum lck)+P.(lc/.(k+1)) by A6,GRCAT_1:def 13 .= (Sum LCk)+P.(lc/.(k+1)) by A10 .= (Sum LCk)+P.(((E/.i)`1)*((E/.i)`2)*((E/.i)`3)) by A3,A16,A19, IDEAL_1:def 12 .= (Sum LCk)+P.(((E/.i)`1)*((E/.i)`2))*P.((E/.i)`3) by A6,ENDALG:def 7 .= (Sum LCk)+P.((E/.i)`1)*P.((E/.i)`2)*P.((E/.i)`3) by A6,ENDALG:def 7 .= (Sum LCk)+LC/.(k+1) by A4,A5,A16,A18 .= Sum (LCk^<*LC/.(k+1)*>) by FVSUM_1:87 .= Sum LC' by A5,A11,A16,A18,FINSEQ_5:11; end; end; A20: for k being Nat holds P[k] from Ind(A7,A9); lc = lc|Seg len lc & LC = LC|Seg len LC by FINSEQ_3:55; hence P.(Sum lc) = Sum LC by A2,A20; end; theorem Th25: :: reformulated QUOFIELD:def 26 proof of symmetry for R, S be non empty doubleLoopStr, P be map of R, S st P is RingIsomorphism holds ex P1 being map of S,R st P1 is RingIsomorphism & P1=P" proof let R, S be non empty doubleLoopStr, P be map of R, S; assume P is RingIsomorphism; then P is RingMonomorphism & P is RingEpimorphism by QUOFIELD:def 24; then A1: P is RingHomomorphism & P is one-to-one & rng P = the carrier of S by QUOFIELD:def 22,def 23; then A2: P is additive multiplicative unity-preserving by QUOFIELD:def 21; A3: rng P = [#]S by A1,PRE_TOPC:12; set P1 = P"; A4: P1 is RingHomomorphism proof for x,y being Element of S holds (P1.(x+y) = P1.x + P1.y & P1.(x*y) = P1.x * P1.y & P1.(1_ S) = 1_ R) proof let x,y be Element of S; consider x' being set such that A5: x' in the carrier of R & P.(x') = x by A1,FUNCT_2:17; reconsider x' as Element of R by A5; consider y' being set such that A6: y' in the carrier of R & P.(y') = y by A1,FUNCT_2:17; reconsider y' as Element of R by A6; A7: x' = ((P qua Function)").(P.(x')) by A1,FUNCT_2:32 .= P1.x by A1,A3,A5,TOPS_2:def 4; A8: y' = ((P qua Function)").(P.(y')) by A1,FUNCT_2:32 .= P1.y by A1,A3,A6,TOPS_2:def 4; A9: P1.(x+y) = P1.(P.(x'+y')) by A2,A5,A6,GRCAT_1:def 13 .= ((P qua Function)").(P.(x'+y')) by A1,A3,TOPS_2:def 4 .= P1.x + P1.y by A1,A7,A8,FUNCT_2:32; A10: P1.(x*y) = P1.(P.(x'*y')) by A2,A5,A6,ENDALG:def 7 .= ((P qua Function)").(P.(x'*y')) by A1,A3,TOPS_2:def 4 .= P1.x * P1.y by A1,A7,A8,FUNCT_2:32; P1.(1_ S) = P1.(P.(1_ R)) by A2,ENDALG:def 8 .= ((P qua Function)").(P.(1_ R)) by A1,A3,TOPS_2:def 4 .= 1_ R by A1,FUNCT_2:32; hence thesis by A9,A10; end; then P1 is additive multiplicative unity-preserving by ENDALG:def 7,def 8,GRCAT_1:def 13; hence thesis by QUOFIELD:def 21; end; P1 is one-to-one by A1,A3,TOPS_2:63; then A11: P1 is RingMonomorphism by A4,QUOFIELD:def 23; rng P1 = [#]R by A1,A3,TOPS_2:62 .= the carrier of R by PRE_TOPC:12; then P1 is RingEpimorphism by A4,QUOFIELD:def 22; then P1 is RingIsomorphism by A11,QUOFIELD:def 24; hence ex P1 being map of S,R st P1 is RingIsomorphism & P1=P"; end; theorem Th26: for R,S being Abelian add-associative right_zeroed right_complementable associative distributive well-unital (non empty doubleLoopStr), F being non empty Subset of R, P being map of R,S st P is RingIsomorphism holds P.:(F-Ideal) = (P.:F)-Ideal proof let R,S being Abelian add-associative right_zeroed right_complementable associative distributive well-unital (non empty doubleLoopStr), F being non empty Subset of R, P being map of R,S;assume A1: P is RingIsomorphism; now let x be set; assume x in P.:(F-Ideal); then consider x' being set such that A2: x' in the carrier of R & x' in F-Ideal & x = P.x' by FUNCT_2:115; consider lc' being LinearCombination of F such that A3: x' = Sum lc' by A2,IDEAL_1:60; consider E being FinSequence of [:the carrier of R, the carrier of R, the carrier of R:] such that A4: E represents lc' by IDEAL_1:35; consider lc being LinearCombination of P.:F such that A5: len lc' = len lc & for i being set st i in dom lc holds lc.i = (P.(E/.i)`1)*(P.(E/.i)`2)*(P.(E/.i)`3) by A4,IDEAL_1:36; P is RingMonomorphism by A1,QUOFIELD:def 24; then P is RingHomomorphism by QUOFIELD:def 23; then x = Sum lc by A2,A3,A4,A5,Th24; hence x in (P.:F)-Ideal by IDEAL_1:60; end; then A6: P.:(F-Ideal) c= (P.:F)-Ideal by TARSKI:def 3; now let x be set; assume A7: x in (P.:F)-Ideal; then consider lc being LinearCombination of P.: F such that A8: x = Sum lc by IDEAL_1:60; P is RingMonomorphism & P is RingEpimorphism by A1,QUOFIELD:def 24; then A9: P is one-to-one & rng P=the carrier of S by QUOFIELD:def 22,def 23; then A10: P is one-to-one & rng P = [#] S by PRE_TOPC:def 3; (P qua Function)" .: (P.:F) = (P qua Function)"(P.:F) by A9,FUNCT_1:155; then A11: (P qua Function)" .: (P.:F) c= F by A9,FUNCT_1:152; A12: (P qua Function)" = P" by A10,TOPS_2:def 4; consider PInv being map of S,R such that A13: PInv is RingIsomorphism & PInv=P" by A1,Th25; consider E be FinSequence of [:the carrier of S, the carrier of S, the carrier of S:] such that A14: E represents lc by IDEAL_1:35; consider lc' being LinearCombination of F such that A15: len lc = len lc' & for i being set st i in dom lc' holds lc'.i = (PInv.(E/.i)`1)*(PInv.(E/.i)`2)*(PInv.(E/.i)`3) by A11,A12,A13,A14,IDEAL_1:36; PInv is RingMonomorphism by A13,QUOFIELD:def 24; then PInv is RingHomomorphism by QUOFIELD:def 23; then PInv.x = Sum lc' by A8,A14,A15,Th24; then A16: PInv.x in F-Ideal by IDEAL_1:60; dom P = the carrier of R by FUNCT_2:def 1; then P.(PInv.x) in P.:(F-Ideal) by A16,FUNCT_1:def 12; hence x in P.:(F-Ideal) by A7,A9,A12,A13,FUNCT_1:57; end; then (P.:F)-Ideal c= P.:(F-Ideal) by TARSKI:def 3; hence P.:(F-Ideal) = (P.:F)-Ideal by A6,XBOOLE_0:def 10; end; theorem Th27: for R,S being Abelian add-associative right_zeroed right_complementable associative distributive well-unital (non empty doubleLoopStr), P being map of R,S st P is RingIsomorphism & R is Noetherian holds S is Noetherian proof let R,S be Abelian add-associative right_zeroed right_complementable associative distributive well-unital (non empty doubleLoopStr), P be map of R,S; assume A1: P is RingIsomorphism & R is Noetherian; now let I be Ideal of S; consider PInv being map of S,R such that A2: PInv is RingIsomorphism & PInv=P" by A1,Th25; reconsider PI=PInv.:I as Ideal of R by A2,Th22; PI is finitely_generated by A1,IDEAL_1:def 27; then consider F being non empty finite Subset of R such that A3: PInv.:I = F-Ideal by IDEAL_1:def 26; P is RingMonomorphism & P is RingEpimorphism by A1,QUOFIELD:def 24; then A4: P is one-to-one & rng P = the carrier of S by QUOFIELD:def 22, def 23; then P is one-to-one & rng P = [#] S by PRE_TOPC:def 3; then P" = (P qua Function)" by TOPS_2:def 4; then A5: P.:(PInv.:I) = P.:(P"I) by A2,A4,FUNCT_1:155; P is RingEpimorphism by A1,QUOFIELD:def 24; then rng P = the carrier of S by QUOFIELD:def 22; then P.:(PInv.:I) = I by A5,FUNCT_1:147; then I = (P.:F)-Ideal by A1,A3,Th26; hence I is finitely_generated; end; hence S is Noetherian by IDEAL_1:def 27; end; theorem Th28: for R being add-associative right_zeroed right_complementable associative distributive well-unital non trivial (non empty doubleLoopStr) holds ex P being map of R, Polynom-Ring (0,R) st P is RingIsomorphism proof let R be add-associative right_zeroed right_complementable associative distributive well-unital non trivial (non empty doubleLoopStr); deffunc F(set)=Bags {}--> $1; consider P being Function such that A1: dom P = the carrier of R and A2: for x being set st x in the carrier of R holds P.x=F(x) from Lambda; now let y be set; hereby assume y in rng P; then consider x being set such that A3: x in the carrier of R & y = P.x by A1,FUNCT_1:def 5; reconsider x as Element of R by A3; reconsider y' = Bags {} --> x as Function of (Bags {} ), R ; Support y' is finite by FINSET_1:13,POLYNOM1:55; then y' is finite-Support Series of 0, R by POLYNOM1:def 10; then y' in the carrier of Polynom-Ring (0,R) by POLYNOM1:def 27; hence y in the carrier of Polynom-Ring (0,R) by A2,A3; end; assume y in the carrier of Polynom-Ring (0,R); then reconsider y'=y as Function of (Bags {}), R by POLYNOM1:def 27; A4: dom y' = Bags {} by FUNCT_2:def 1; then A5: rng y' = {y'.{}} by FUNCT_1:14,POLYNOM1:55; then A6: y' = Bags {} --> y'.{} by A4,FUNCOP_1:15; y'.{} in rng y' by A5,TARSKI:def 1; then reconsider x = y'.{} as Element of R; y = P.x by A2,A6 ; hence y in rng P by A1,FUNCT_1:def 5; end; then A7: rng P = the carrier of Polynom-Ring (0,R) by TARSKI:2; then P is Function of the carrier of R, the carrier of Polynom-Ring (0,R) by A1,FUNCT_2:3; then reconsider P as map of R, Polynom-Ring (0,R); take P; now let x,y be Element of R; reconsider Px = P.x, Py = P.y, Pxy = P.(x+y) as Polynomial of 0, R by POLYNOM1:def 27; now let z be bag of 0; A8: z in Bags {} by POLYNOM1:def 14; A9: Pxy.z = (Bags {} --> x+y).z by A2 .= x+y by A8,FUNCOP_1:13; A10: Px.z = (Bags {} --> x).z by A2 .= x by A8,FUNCOP_1:13; Py.z = (Bags {} --> y).z by A2 .= y by A8,FUNCOP_1:13; hence Pxy.z = Px.z + Py.z by A9,A10; end; then Pxy = Px + Py by POLYNOM1:def 21; hence P.x+P.y = P.(x+y) by POLYNOM1:def 27; end; then A11: P is additive by GRCAT_1:def 13; now let x,y be Element of R; reconsider Px = P.x, Py = P.y, Pxy = P.(x*y) as Polynomial of 0, R by POLYNOM1:def 27; now let b be bag of 0; reconsider s = <* x*y *> as FinSequence of the carrier of R; take s; A12: b in Bags {} by POLYNOM1:def 14; thus Pxy.b = (Bags {} --> x*y).b by A2 .= x*y by A12,FUNCOP_1:13 .= Sum s by RLVECT_1:61; A13: decomp b = <* <* {}, {} *> *> by Th2; A14: len s = 1 by FINSEQ_1:56; A15: len decomp b = 1 by A13,FINSEQ_1:56; thus len s = len decomp b by A13,A14,FINSEQ_1:56; now let k be Nat; assume A16: k in dom s; then A17: 1 <= k & k <= 1 by A14,FINSEQ_3:27; then A18: k = 1 by AXIOMS:21; set b1 = {}, b2 = {}; A19: b1 in Bags {} & b2 in Bags {} by POLYNOM1:55,TARSKI:def 1; then reconsider b1, b2 as bag of 0 by POLYNOM1:def 14; take b1, b2; k in dom decomp b by A15,A17,FINSEQ_3:27 ; hence (decomp b)/.k = (decomp b).1 by A18,FINSEQ_4:def 4 .= <*b1, b2*> by A13,FINSEQ_1:57; A20: Px.b1 = (Bags {} --> x).b1 by A2 .= x by A19,FUNCOP_1:13; A21: Py.b2 = (Bags {} --> y).b2 by A2 .= y by A19,FUNCOP_1:13; thus s/.k = s.1 by A16,A18,FINSEQ_4:def 4 .= Px.b1*Py.b2 by A20 ,A21,FINSEQ_1:57; end; hence for k being Nat st k in dom s ex b1, b2 being bag of 0 st (decomp b)/.k = <*b1, b2*> & s/.k = Px.b1*Py.b2; end; then Pxy = Px *' Py by POLYNOM1:def 26; hence P.x*P.y = P.(x*y) by POLYNOM1:def 27; end; then A22: P is multiplicative by ENDALG:def 7; EmptyBag {} = {} --> 0 by POLYNOM1:def 15; then dom EmptyBag {} = {} by FUNCOP_1:16; then A23: EmptyBag 0 = {} by RELAT_1:64; A24: dom ({{}} --> 0.R) = {{}} by FUNCT_2:def 1; then A25: {} in dom ({{}} --> 0.R) by TARSKI:def 1; A26: dom ({{}} --> 1.R) = {{}} by FUNCT_2:def 1; 1_ Polynom-Ring (0, R) = 1_ (0,R) by POLYNOM1:def 27 .= 0_ (0,R)+*({},1.R) by A23,POLYNOM1:def 25 .= ({{}} --> 0.R)+*({},1.R) by POLYNOM1:55,def 24 .= ({{}} --> 0.R)+*({} .--> 1.R) by A25,FUNCT_7:def 3 .= ({{}} --> 0.R)+*({{}} --> 1.R) by CQC_LANG:def 2 .= ({{}} --> 1.R) by A24,A26,FUNCT_4:20 .= ({{}} --> 1_ R) by POLYNOM2:3 .= P.(1_ R)by A2,POLYNOM1:55; then P is unity-preserving by ENDALG:def 8; then A27: P is RingHomomorphism by A11,A22,QUOFIELD:def 21; now let x1,x2 be set; assume A28: x1 in dom P & x2 in dom P; assume P.x1 = P.x2; then (Bags {} --> x1) = P.x2 by A2,A28; then (Bags {} --> x1) = (Bags {} --> x2) by A2,A28; hence x1 = x2 by FUNCT_4:7; end; then P is one-to-one by FUNCT_1:def 8; then A29: P is RingMonomorphism by A27,QUOFIELD:def 23; P is RingEpimorphism by A7,A27,QUOFIELD:def 22; hence P is RingIsomorphism by A29,QUOFIELD:def 24; end; theorem Th29: for R being right_zeroed add-associative right_complementable unital distributive non trivial (non empty doubleLoopStr), n being Nat, b being bag of n, p1 being Polynomial of n, R, F being FinSequence of the carrier of Polynom-Ring (n,R) st p1 = Sum F ex g being Function of the carrier of Polynom-Ring (n, R), the carrier of R st (for p being Polynomial of n, R holds g.p = p.b) & p1.b = Sum (g*F) proof let R be right_zeroed add-associative right_complementable unital distributive non trivial (non empty doubleLoopStr), n be Nat, b be bag of n,p1 be Polynomial of n, R, F be FinSequence of the carrier of Polynom-Ring (n,R); assume A1: p1 = Sum F; set PNR = Polynom-Ring (n,R); set CPNR = the carrier of PNR; set CR = the carrier of R; defpred P1[Element of CPNR, Element of CR] means for p being Polynomial of n, R st p = $1 holds $2 = p.b; A2: now let x be Element of CPNR; reconsider x'=x as Polynomial of n, R by POLYNOM1:def 27; P1[x,x'.b]; hence ex y being Element of CR st P1[x,y]; end; consider g be Function of CPNR,CR such that A3: for x being Element of CPNR holds P1[x,g.x] from FuncExD(A2); take g; now let p be Polynomial of n,R; reconsider p'=p as Element of CPNR by POLYNOM1:def 27; P1[p',g.p'] by A3 ; hence g.p = p.b; end; hence for p being Polynomial of n, R holds g.p = p.b; defpred P2[Nat] means for F' being FinSequence of CPNR, p1' being Polynomial of n, R st len F' <= $1 & p1' = Sum F' holds p1'.b = Sum (g * F'); A4: P2[0] proof let F' being FinSequence of CPNR, p1' be Polynomial of n, R; assume A5: len F' <= 0 & p1' = Sum F'; then len F' = 0 by NAT_1:18; then A6: F' = <*> (CPNR) by FINSEQ_1:25; then A7: p1' = 0.PNR by A5,RLVECT_1:60 .= 0_(n, R) by POLYNOM1:def 27; rng F' c= CPNR; then rng F' c= dom g by FUNCT_2:def 1; then dom (g * F') = dom F' by RELAT_1:46; then g * F' = <*> (CR) by A6,RELAT_1:60,64; then Sum (g * F') = 0.R by RLVECT_1:60; hence p1'.b = Sum (g * F') by A7,POLYNOM1:81; end; A8: for k being Nat st P2[k] holds P2[k+1] proof let k be Nat; assume A9: P2[k]; now let F' be FinSequence of CPNR, p1' be Polynomial of n, R; assume A10: len F' <= k+1 & p1' = Sum F'; per cases; suppose len F' < k+1; then len F' <= k by NAT_1:38; hence p1'.b = Sum (g * F') by A9,A10; suppose len F' >= k+1; then len F' = k+1 by A10,AXIOMS:21; then consider p,q being FinSequence such that A11: len p = k & len q = 1 & F' = p^q by FINSEQ_2:25; rng p c= rng F' by A11,FINSEQ_1:42; then rng p c= CPNR by XBOOLE_1:1; then reconsider p as FinSequence of CPNR by FINSEQ_1:def 4; reconsider p' = Sum p as Polynomial of n, R by POLYNOM1:def 27; A12: p'.b = Sum (g * p) by A9,A11; rng q c= rng F' by A11,FINSEQ_1:43 ; then rng q c= CPNR by XBOOLE_1:1; then reconsider q as FinSequence of CPNR by FINSEQ_1:def 4; 1 in dom q by A11,FINSEQ_3:27; then q.1 in rng q by FUNCT_1:def 5; then reconsider q'=q.1 as Element of CPNR; A13: q = <* q' *> by A11,FINSEQ_1:57; then A14: q' = Sum q by RLVECT_1:61; reconsider q''=q' as Polynomial of n, R by POLYNOM1:def 27; g * q = <* g.q' *> by A13,FINSEQ_2:39 .= <* q''.b *> by A3; then A15: Sum (g * q) = q''.b by RLVECT_1:61; A16: Sum F' = Sum p + Sum q by A11,RLVECT_1:58; A17: g * F' = (g * p)^(g* q) by A11,FINSEQOP:10; p1' = p' + q'' by A10,A14,A16,POLYNOM1:def 27; hence p1'.b = Sum (g * p) + Sum (g * q) by A12,A15,POLYNOM1:def 21 .= Sum (g * F') by A17,RLVECT_1:58; end; hence P2[k+1]; end; for k being Nat holds P2[k] from Ind(A4,A8); then P2[len F]; hence thesis by A1; end; definition let R be Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n be Nat; func upm (n,R) -> map of Polynom-Ring (Polynom-Ring(n,R)), Polynom-Ring(n+1,R) means :Def6: for p1 being (Polynomial of Polynom-Ring (n,R)), p2 being (Polynomial of n, R), p3 being (Polynomial of (n+1), R), b being bag of n+1 st p3 = it.p1 & p2 = p1.(b.n) holds p3.b = p2.(b|n); existence proof set PRPNR = Polynom-Ring (Polynom-Ring(n,R)); set PN1R = Polynom-Ring(n+1,R); set PNR = Polynom-Ring(n,R); set CPRPNR = the carrier of PRPNR; set CPN1R = the carrier of PN1R; set CR = the carrier of R; defpred P1[Element of CPRPNR, Element of CPN1R] means for p1 being (Polynomial of PNR), p2 being (Polynomial of n, R), p3 being (Polynomial of (n+1), R), b being bag of n+1 st p1 = $1 & p3 = $2 & p2 = p1.(b.n) holds p3.b = p2.(b|n); A1: now let x being Element of CPRPNR; reconsider p1=x as Polynomial of PNR by POLYNOM3:def 12; defpred P2[Element of Bags (n+1), Element of CR] means for p2 being (Polynomial of n, R) st p2 = p1.($1.n) holds $2 = p2.($1|n); A2: now let b be Element of Bags (n+1); reconsider p2 = p1.(b.n) as Polynomial of n, R by POLYNOM1:def 27; n < n+1 by REAL_1:69; then reconsider bn = b|n as bag of n by Th3 ; P2[b,p2.bn]; hence ex r being Element of CR st P2[b,r]; end; consider y being Function of Bags (n+1), CR such that A3: for b being Element of Bags (n+1) holds P2[b,y.b] from FuncExD(A2); reconsider y as Function of Bags (n+1), R ; reconsider y as Series of (n+1), R ; deffunc F(set)={ b where b is Element of Bags (n+1) : b.n = $1 & for p2 being Polynomial of n, R st p2 = p1.$1 holds b|n in Support p2 }; A4: now let k be set; assume k in NAT; set Ak = F(k); Ak c= Bags (n+1) proof let b be set; assume b in Ak; then consider b' being Element of Bags (n+1) such that A5: b'=b & b'.n = k & for p2 being Polynomial of n, R st p2 = p1.k holds b'|n in Support p2; thus thesis by A5; end; hence Ak in bool Bags (n+1); end; consider A being Function of NAT,bool Bags (n+1) such that A6: for k being set st k in NAT holds A.k =F(k) from Lambda1(A4); now let X be set; assume X in A .: len p1; then consider k being Nat such that A7: k in len p1 & X = A.k by FUNCT_2:116; A8: A.k = { b where b is Element of Bags (n+1) : b.n = k & for p2 being Polynomial of n, R st p2 = p1.k holds b|n in Support p2 } by A6; reconsider p2 = p1.k as Polynomial of n, R by POLYNOM1:def 27; per cases; suppose A9: Support p2 = {}; now assume A.k <> {}; then consider b being set such that A10: b in A.k by XBOOLE_0:def 1; consider b' being Element of Bags (n+1) such that A11: b'=b & b'.n = k & for p2 being Polynomial of n, R st p2 = p1.k holds b'|n in Support p2 by A8,A10 ; thus contradiction by A9,A11; end; hence X is finite by A7; suppose A12: Support p2 <> {}; then consider b2 being set such that A13: b2 in Support p2 by XBOOLE_0:def 1; reconsider b2 as Element of Bags n by A13; A14: (b2 bag_extend k).n = k by Def1; for p2 being Polynomial of n, R st p2 = p1.k holds (b2 bag_extend k)|n in Support p2 by A13,Def1; then (b2 bag_extend k) in A.k by A8,A14; then reconsider Ak = A.k as non empty set; reconsider Support_p2 = Support p2 as non empty set by A12; defpred P3[Element of Ak, Element of Support_p2] means for b being Element of Bags (n+1) st $1 = b holds $2 = b|n; A15: now let x be Element of Ak; x in A.k; then consider b being Element of Bags (n+1) such that A16: b=x & b.n = k & for p2 being Polynomial of n, R st p2 = p1.k holds b|n in Support p2 by A8; reconsider bn = b|n as Element of Support_p2 by A16; P3[x,bn] by A16; hence ex y being Element of Support_p2 st P3[x,y]; end; consider f being Function of Ak,Support_p2 such that A17: for x being Element of Ak holds P3[x,f.x] from FuncExD(A15); A18: dom f = Ak by FUNCT_2:def 1; now let x1,x2 be set; assume A19: x1 in dom f & x2 in dom f & f.x1 = f.x2; then consider b1 being Element of Bags (n+1) such that A20: b1=x1 & b1.n = k & for p2 being Polynomial of n, R st p2 = p1.k holds b1|n in Support p2 by A8,A18 ; f.x1 in Support_p2 by A19,FUNCT_2:7; then reconsider fx1 = f.x1 as Element of Bags n; b1|n = f.x1 by A17,A19,A20; then A21: b1 = fx1 bag_extend k by A20,Def1; consider b2 being Element of Bags (n+1) such that A22: b2=x2 & b2.n = k & for p2 being Polynomial of n, R st p2 = p1.k holds b2|n in Support p2 by A8,A18,A19 ; b2|n = f.x1 by A17,A19,A22; hence x1 = x2 by A20,A21,A22,Def1; end; then A23: f is one-to-one by FUNCT_1:def 8; rng f c= Support_p2 ; then Card Ak <=` Card Support_p2 by A18,A23,CARD_1:26; hence X is finite by A7,CARD_2:68; end; then A24: union (A .: len p1) is finite by FINSET_1:25; Support y c= union (A .: len p1) proof let x be set; assume A25: x in Support y; then reconsider x'=x as Element of Bags (n+1); A26: y.x' <> 0.R by A25,POLYNOM1:def 9; reconsider p2 = p1.(x'.n) as Polynomial of n, R by POLYNOM1:def 27; n < n+1 by REAL_1:69; then reconsider xn = x'|n as Element of Bags n by Th3; A27: p2.(xn) <> 0.R by A3,A26; then A28: for p2 being Polynomial of n, R st p2 = p1.(x'.n) holds xn in Support p2 by POLYNOM1:def 9; A.(x'.n) = { b where b is Element of Bags (n+1) : b.n = x'.n & for p2 being Polynomial of n, R st p2 = p1.(x'.n) holds b|n in Support p2 } by A6; then A29: x in A.(x'.n) by A28; p2 <> 0_ (n, R) by A27,POLYNOM1:81; then p2 <> 0.PNR by POLYNOM1:def 27; then A30: x'.n < len p1 by ALGSEQ_1:22; len p1 = { i where i is Nat : i < len p1 } by AXIOMS:30; then A31: x'.n in len p1 by A30 ; dom A = NAT by FUNCT_2:def 1; then A.(x'.n) in A .: len p1 by A31,FUNCT_1:def 12; hence x in union (A .: len p1) by A29,TARSKI:def 4; end; then Support y is finite by A24,FINSET_1:13; then y is finite-Support by POLYNOM1:def 10; then reconsider y'=y as Element of CPN1R by POLYNOM1:def 27; now let p1 be (Polynomial of PNR), p2 be (Polynomial of n, R), p3 be (Polynomial of (n+1), R), b be bag of n+1; assume A32: p1 = x & p3 = y' & p2 = p1.(b.n); b is Element of Bags (n+1) by POLYNOM1:def 14; hence p3.b = p2.(b|n) by A3,A32; end; hence ex y being Element of CPN1R st P1[x,y]; end; consider P being Function of CPRPNR,CPN1R such that A33: for x being Element of CPRPNR holds P1[x,P.x] from FuncExD (A1); reconsider P as map of PRPNR, PN1R; take P; now let p1 being (Polynomial of Polynom-Ring (n,R)), p2 being (Polynomial of n, R), p3 being (Polynomial of (n+1), R), b being bag of n+1; assume A34: p3 = P.p1 & p2 = p1.(b.n); p1 in CPRPNR by POLYNOM3:def 12; hence p3.b = p2.(b|n) by A33,A34; end; hence thesis; end; uniqueness proof set PNR = Polynom-Ring(n,R); set CPRPNR = the carrier of Polynom-Ring (Polynom-Ring(n,R)); set CPN1R = the carrier of Polynom-Ring(n+1,R); let A, B be map of Polynom-Ring (Polynom-Ring(n,R)), Polynom-Ring(n+1,R);assume A35: for p1 being (Polynomial of Polynom-Ring (n,R)), p2 being (Polynomial of n, R), p3 being (Polynomial of (n+1), R), b being bag of n+1 st p3 = A.p1 & p2 = p1.(b.n) holds p3.b = p2.(b|n); assume A36: for p1 being (Polynomial of Polynom-Ring (n,R)), p2 being (Polynomial of n, R), p3 being (Polynomial of (n+1), R), b being bag of n+1 st p3 = B.p1 & p2 = p1.(b.n) holds p3.b = p2.(b|n); now let x be set; assume A37: x in CPRPNR; then reconsider x'=x as Polynomial of PNR by POLYNOM3:def 12; A.x in CPN1R & B.x in CPN1R by A37,FUNCT_2:7; then reconsider Ax=A.x, Bx=B.x as (Polynomial of n+1,R) by POLYNOM1:def 27; now let b be set; assume b in Bags (n+1); then reconsider b'=b as Element of Bags (n+1); n < n+1 by NAT_1:38; then reconsider bn = (b'|n) as Element of Bags n by Th3; reconsider p2 = x'.(b'.n) as Polynomial of n, R by POLYNOM1:def 27; thus Ax.b = p2.bn by A35 .= Bx.b by A36; end; hence A.x = B.x by FUNCT_2:18; end; hence A=B by FUNCT_2:18; end; end; definition let R be Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n be Nat; cluster upm (n,R) -> additive; coherence proof set PNR = Polynom-Ring(n,R); set P = upm (n,R); thus P is additive proof let x,y be Element of Polynom-Ring (Polynom-Ring(n,R)); reconsider x'=x, y'=y, xy'=x+y as Polynomial of PNR by POLYNOM3:def 12; A1: xy' = x'+y' by POLYNOM3:def 12; reconsider Pxy = P.(x+y), Px = P.x, Py = P.y as (Polynomial of n+1, R) by POLYNOM1:def 27; now let b be set; assume b in Bags (n+1); then reconsider b'=b as bag of n+1 by POLYNOM1:def 14; reconsider xbn=x'.(b'.n), ybn = y'.(b'.n) as Polynomial of n, R by POLYNOM1:def 27; n < n+1 by REAL_1:69; then reconsider bn = b'|n as bag of n by Th3 ; reconsider xybn = (x'+y').(b'.n) as Polynomial of n,R by POLYNOM1:def 27; (x'+y').(b'.n) = x'.(b'.n)+y'.(b'.n) by POLYNOM3:def 6; then A2: xybn = xbn + ybn by POLYNOM1:def 27; A3: xbn.bn = Px.b' & ybn.bn = Py.b' by Def6; thus Pxy.b = (xbn + ybn).bn by A1,A2,Def6 .= Px.b' + Py.b' by A3, POLYNOM1:def 21 .= (Px + Py).b by POLYNOM1:def 21; end; hence P.(x+y) = Px+Py by FUNCT_2:18 .= P.x + P.y by POLYNOM1:def 27 ; end;:: TRIANG_1:def 2 end; cluster upm (n,R) -> multiplicative; coherence proof set PNR = Polynom-Ring(n,R); set CPNR = the carrier of PNR; set CR = the carrier of R; set P = upm (n,R); thus P is multiplicative proof let x',y' be Element of the carrier of Polynom-Ring (Polynom-Ring(n,R)); reconsider x=x', y=y', xy = x'*y' as Polynomial of PNR by POLYNOM3:def 12; reconsider Pxy = P.(x'*y'), PxPy = (P.x')*(P.y'), Px=P.x', Py=P.y' as Polynomial of n+1,R by POLYNOM1:def 27; A4: PxPy = Px*'Py by POLYNOM1:def 27; A5: xy = x*'y by POLYNOM3:def 12; now let b' be set; assume b' in Bags (n+1); then reconsider b=b' as Element of Bags (n+1); consider r be FinSequence of CPNR such that A6: len r = (b.n)+1 & (xy).(b.n) = Sum r & for k be Nat st k in dom r holds r.k = x.(k-'1)*y.((b.n)+1-'k) by A5,POLYNOM3:def 11; n < n+1 by NAT_1:38; then reconsider bn=b|n as Element of Bags n by Th3; reconsider xybn=xy.(b.n) as Polynomial of n,R by POLYNOM1:def 27; consider g being Function of CPNR, CR such that A7: (for p being Polynomial of n, R holds g.p = p.bn) & xybn.bn = Sum (g * r) by A6,Th29; A8: Sum (g * r) = Pxy.b by A7,Def6; defpred P3[set, set] means for p,q being Polynomial of n,R, fcr being FinSequence of CR, i being Nat st i = $1 & p = x.(i-'1) & q = y.((b.n)+1-'i) & fcr = $2 holds (p*'q).bn = Sum fcr & len fcr = len decomp bn & for k being Nat st k in dom fcr holds ex b1, b2 being bag of n st (decomp bn)/.k = <*b1, b2*> & fcr/.k = p.b1*q.b2; A9: now let e' be set; assume e' in dom r; then reconsider e=e' as Nat; reconsider p = x.(e-'1), q = y.((b.n)+1-'e) as Polynomial of n, R by POLYNOM1:def 27; consider fcr being FinSequence of CR such that A10: (p*'q).bn = Sum fcr & len fcr = len decomp bn & for k being Nat st k in dom fcr holds ex b1, b2 being bag of n st (decomp bn)/.k = <*b1, b2*> & fcr/.k = p.b1*q.b2 by POLYNOM1:def 26; A11: P3[e,fcr] by A10; fcr in CR* by FINSEQ_1:def 11; hence ex u being set st u in CR* & P3[e',u] by A11; end; consider s being Function of dom r, CR* such that A12: for e being set st e in dom r holds P3[e,s.e] from FuncEx1(A9); A13: dom s = dom r by FUNCT_2:def 1; then ex n being Nat st dom s = Seg n by FINSEQ_1:def 2; then A14: s is FinSequence-like by FINSEQ_1:def 2; rng s c= CR*; then reconsider s as FinSequence of CR* by A14,FINSEQ_1:def 4; len (Sum s) = len s by MATRLIN:def 8; then A15: dom (Sum s) = dom r by A13,FINSEQ_3:31; A16: dom r = dom (g * r) by ALG_1:1; now let k be Nat; assume A17: k in dom r; then A18: (Sum s)/.k = (Sum s).k by A15,FINSEQ_4:def 4; A19: s/.k = s.k by A13,A17,FINSEQ_4:def 4; reconsider sk=s.k as Element of CR* by A17,FUNCT_2:7; reconsider sk as FinSequence of CR; reconsider p = x.(k-'1), q = y.((b.n)+1-'k) as Polynomial of n, R by POLYNOM1:def 27; reconsider pq' = p *' q as Element of CPNR by POLYNOM1:def 27; A20: r.k = x.(k-'1)*y.((b.n)+1-'k) by A6,A17 .= pq' by POLYNOM1:def 27; thus (Sum s).k = Sum sk by A15,A17,A18,A19,MATRLIN:def 8 .= (p*'q).bn by A12,A17 .= g.(r.k) by A7,A20 .= (g * r).k by A17,FUNCT_1:23; end; then A21: Sum s = g * r by A15,A16,FINSEQ_1:17; set t = FlattenSeq s; A22: Sum t = Pxy.b by A8,A21,POLYNOM1:34; consider u being FinSequence of CR such that A23: PxPy.b = Sum u & len u = len decomp b & for k being Nat st k in dom u ex b1, b2 being bag of n+1 st (decomp b)/.k = <*b1, b2*> & u/.k = Px.b1*Py.b2 by A4,POLYNOM1:def 26; defpred P1[set, set] means for i,n1 being Nat, b1 being bag of n+1 st n1=$1 & b1 = (divisors b).n1 & i in dom (divisors bn) & (divisors bn).i = b1|n holds b1.n+1 in dom s & i in dom (s.(b1.n+1)) & $2 = (Sum Card (s|(b1.n+1-'1))) + i; A24: now let n1' be set; assume A25: n1' in dom u; then reconsider n1=n1' as Nat; dom u = dom decomp b by A23,FINSEQ_3:31 .= dom divisors b by POLYNOM1:def 19; then A26: (divisors b).n1 in rng divisors b by A25,FUNCT_1:def 5; then reconsider b1=(divisors b).n1 as bag of n+1 by POLYNOM1: def 14; n < n+1 by NAT_1:38; then reconsider b1n=b1|n as Element of Bags n by Th3; A27: b1 divides b by A26,Th7; then b1n divides bn by Th4; then b1n in rng divisors bn by Th7; then consider i being set such that A28: i in dom divisors bn & b1n = (divisors bn).i by FUNCT_1:def 5; reconsider i as Nat by A28; set n2 = (Sum Card (s|(b1.n+1-'1))) + i; b1.n <= b.n by A27,POLYNOM1:def 13; then A29: b1.n +1 <= b.n+1 by AXIOMS:24; b1.n >= 0 by NAT_1:18; then A30: b1.n +1 >= 1+0 by AXIOMS:24; then A31: b1.n+1 in dom s by A6,A13,A29,FINSEQ_3:27; reconsider p=x.((b1.n+1)-'1), q=y.((b.n)+1-'(b1.n+1)) as Polynomial of n,R by POLYNOM1:def 27; s.(b1.n+1) is Element of CR* by A13,A31,FUNCT_2:7; then p = x.((b1.n+1)-'1) & q = y.((b.n)+1-'(b1.n+1)) & s.(b1.n+1) is FinSequence of CR; then len (s.(b1.n+1)) = len decomp bn by A12,A13,A31; then A32: dom (s.(b1.n+1)) = dom decomp bn by FINSEQ_3:31 .= dom divisors bn by POLYNOM1:def 19; then A33: n2 in dom t by A28,A31,POLYNOM1:33; for i',n1' being Nat, b1' being bag of n+1 st n1'=n1 & b1' = (divisors b).n1' & i' in dom (divisors bn) & (divisors bn).i' = b1'|n holds b1'.n+1 in dom s & i' in dom (s.(b1'.n+1)) & n2 = (Sum Card (s|(b1'.n+1-'1))) + i' by A6,A13,A28,A29,A30, A32,FINSEQ_3:27,FUNCT_1:def 8; hence ex n2' being set st n2' in dom t & P1[n1',n2'] by A33; end; consider p being Function of dom u, dom t such that A34: for x being set st x in dom u holds P1[x,p.x] from FuncEx1(A24); A35: now let n1 be Nat; assume A36: n1 in dom u; then consider b1, b2 being bag of n+1 such that A37: (decomp b)/.n1 = <*b1, b2*> & u/.n1 = Px.b1*Py.b2 by A23; reconsider xb1n = x.(b1.n), yb2n=y.(b2.n) as Polynomial of n,R by POLYNOM1:def 27; n < n+1 by NAT_1:38; then reconsider b1n = b1|n, b2n=b2|n as Element of Bags n by Th3; A38: u.n1 = Px.b1*Py.b2 by A36,A37,FINSEQ_4:def 4 .= xb1n.b1n * Py.b2 by Def6 .= xb1n.b1n * yb2n.b2n by Def6; (divisors b)/.n1 is Element of Bags (n+1); then reconsider b1' = (divisors b)/.n1 as bag of n+1; A39: dom u = dom decomp b by A23,FINSEQ_3:31; then <* b1,b2 *> = <* b1',b-' b1' *> by A36,A37,POLYNOM1:def 19 ; then A40: b1 = b1' & b2 = b -' b1' by GROUP_7:2; A41: n1 in dom divisors b by A36,A39,POLYNOM1:def 19; then A42: b1 = (divisors b).n1 by A40,FINSEQ_4:def 4; then b1 in rng divisors b by A41,FUNCT_1:def 5; then A43: b1 divides b by Th7; then b1n divides bn by Th4; then b1n in rng divisors bn by Th7; then consider i being set such that A44: i in dom divisors bn & b1n = (divisors bn).i by FUNCT_1:def 5; reconsider i as Nat by A44; A45: b1.n+1 in dom s & i in dom (s.(b1.n+1)) & p.n1 = (Sum Card (s|(b1.n+1-'1))) + i by A34,A36,A42,A44 ; then A46: t.(p.n1) = (s.(b1.n+1)).i by POLYNOM1:33; A47: b1.n+1-'1 = b1.n+1-1 by JORDAN4:2 .= b1.n by XCMPLX_1:26; A48: b1.n <= b.n by A43,POLYNOM1:def 13; then b1.n + 1 <= b.n + 1 by AXIOMS:24; then A49: b.n+1 -' (b1.n+1) = b.n+1-(b1.n+1) by SCMFSA_7:3 .= b.n+1-b1.n-1 by XCMPLX_1:36 .= b.n-b1.n+1-1 by XCMPLX_1:29 .= b.n-b1.n by XCMPLX_1:26 .= b.n -' b1.n by A48,SCMFSA_7:3 .= b2.n by A40,POLYNOM1:def 6; s.(b1.n+1) is Element of CR* by A13,A45,FUNCT_2:7; then reconsider sb1n1=s.(b1.n+1) as FinSequence of CR; xb1n = x.((b1.n+1)-'1) & yb2n = y.((b.n)+1-'(b1.n+1)) & s.(b1.n+1)=sb1n1 by A47,A49; then A50: (xb1n*'yb2n).bn = Sum sb1n1 & len sb1n1 = len decomp bn & for k being Nat st k in dom sb1n1 holds ex b1, b2 being bag of n st (decomp bn)/.k = <*b1, b2*> & sb1n1/.k = xb1n.b1*yb2n.b2 by A12,A13,A45; consider B1, B2 being bag of n such that A51: (decomp bn)/.i=<*B1,B2*> & sb1n1/.i=xb1n.B1*yb2n.B2 by A12,A13, A45,A47,A49; (divisors bn)/.i is Element of Bags n; then reconsider B1' = (divisors bn)/.i as bag of n; A52: dom divisors bn = dom decomp bn by POLYNOM1:def 19; then <*B1,B2*> = <* B1',bn -' B1' *> by A44,A51,POLYNOM1:def 19 ; then A53: B1 = B1' & B2 = bn -' B1' by GROUP_7:2; then A54: B1 = b1n by A44,FINSEQ_4:def 4; then A55: B2 = b2n by A40,A53,Th5; dom sb1n1 = dom divisors bn by A50,A52,FINSEQ_3:31; hence u.n1 = t.(p.n1) by A38,A44,A46,A51,A54,A55,FINSEQ_4:def 4 ; end; A56: dom decomp b <> {}; b.n >= 0 by NAT_1:18; then 1 <= 1 & 0+1 <= len r by A6,AXIOMS:24; then A57: 1 in dom s by A13,FINSEQ_3:27; then 1 in dom Card s by CARD_3:def 2; then Sum Card s >= (Card s).1 by POLYNOM3:4; then A58: Sum Card s >= len (s.1) by A57,CARD_3:def 2; now reconsider p'=x.(1-'1), q'=y.((b.n)+1-'1) as Polynomial of n, R by POLYNOM1:def 27; s/.1 is FinSequence of CR; then A59: s.1 is FinSequence of CR by A57,FINSEQ_4:def 4; p'=x.(1 -'1) & q'=y.((b.n)+1-'1); then len (s.1) = len decomp bn by A12,A13,A57,A59; hence len (s.1) <> 0 by FINSEQ_1:25; end; then Sum Card s > 0 by A58,NAT_1:19; then len t > 0 by POLYNOM1:30; then t <> {} by FINSEQ_1:25; then A60: dom u <> {} & dom t <> {} by A23,A56,FINSEQ_3:31,RELAT_1:64; now let n1',n2' be set; assume A61: n1' in dom p & n2' in dom p & p.n1' = p.n2'; dom p = dom u by A60,FUNCT_2:def 1; then reconsider n1=n1', n2=n2' as Nat by A61; A62: dom u = dom decomp b by A23,FINSEQ_3:31 .= dom divisors b by POLYNOM1:def 19; then A63: (divisors b).n1 in rng divisors b by A61,FUNCT_1:def 5; then reconsider b1=(divisors b).n1 as bag of n+1 by POLYNOM1: def 14; A64: (divisors b).n2 in rng divisors b by A61,A62,FUNCT_1:def 5 ; then reconsider b2=(divisors b).n2 as bag of n+1 by POLYNOM1: def 14; n < n+1 by NAT_1:38; then reconsider b1n=b1|n, b2n=b2|n as Element of Bags n by Th3; b1 divides b by A63,Th7; then b1n divides bn by Th4; then b1n in rng divisors bn by Th7; then consider i1 being set such that A65: i1 in dom divisors bn & b1n = (divisors bn).i1 by FUNCT_1:def 5; reconsider i1 as Nat by A65; b2 divides b by A64,Th7; then b2n divides bn by Th4; then b2n in rng divisors bn by Th7; then consider i2 being set such that A66: i2 in dom divisors bn & b2n = (divisors bn).i2 by FUNCT_1:def 5; reconsider i2 as Nat by A66; A67: b1.n+1 in dom s & i1 in dom (s.(b1.n+1)) & p.n1 = (Sum Card (s|(b1.n+1-'1))) + i1 by A34,A61,A65; A68: b2.n+1 in dom s & i2 in dom (s.(b2.n+1)) & p.n2 = (Sum Card (s|(b2.n+1-'1))) + i2 by A34,A61,A66; (Card s)|(b1.n+1-'1) = Card (s|(b1.n+1-'1)) & (Card s)|(b2.n+1-'1) = Card (s|(b2.n+1-'1)) by POLYNOM3:16; then A69: b1.n+1 = b2.n+1 & i1=i2 by A61,A67,A68,POLYNOM3:22; then A70: b1.n = b2.n by XCMPLX_1:2; A71: b1 is Element of Bags (n+1) & b2 is Element of Bags (n+1) by POLYNOM1:def 14; then b1 = b1n bag_extend b1.n by Def1 .= b2 by A65,A66,A69,A70, A71,Def1; hence n1' = n2' by A61,A62,FUNCT_1:def 8; end; then A72: p is one-to-one by FUNCT_1:def 8; dom t c= rng p proof let n1' be set; assume A73: n1' in dom t; then reconsider n1=n1' as Nat; consider i, j being Nat such that A74: i in dom s & j in dom (s.i) & n1 = (Sum Card (s|(i-'1))) + j & (s.i).j = t.n1 by A73,POLYNOM1:32; reconsider p' = x.(i-'1), q' = y.((b.n)+1-'i) as Polynomial of n,R by POLYNOM1:def 27; reconsider bj=(divisors bn)/.j as bag of n by POLYNOM1:def 14; s.i in CR* by A13,A74,FUNCT_2:7; then i is Nat & p' = x.(i-'1) & q' = y.((b.n)+1-'i) & s.i is FinSequence of CR by FINSEQ_1:def 11; then len (s.i) = len decomp bn by A12,A13,A74; then A75: dom (s.i) = dom decomp bn by FINSEQ_3:31 .= dom divisors bn by POLYNOM1:def 19; then A76: bj = (divisors bn).j by A74,FINSEQ_4:def 4; then bj in rng divisors bn by A74,A75,FUNCT_1:def 5; then A77: bj divides bn by Th7; set bij = bj bag_extend (i -' 1); now let k be set; per cases; suppose A78: k in n+1; now per cases; suppose A79: k in n; then A80: bij.k = (bij|n).k by FUNCT_1:72 .= bj.k by Def1; b.k = bn.k by A79,FUNCT_1:72; hence bij.k <= b.k by A77,A80,POLYNOM1:def 13; suppose A81: not k in n; n+1 = succ n by CARD_1:52 .= n \/ {n} by ORDINAL1:def 1; then k in {n} by A78,A81,XBOOLE_0:def 2; then A82: k = n by TARSKI:def 1; then A83: bij.k = i -' 1 by Def1; A84: 1 <= i & i <= b.n+1 by A6,A13,A74,FINSEQ_3:27; then i - 1 <= b.n + 1 - 1 by REAL_1:49; then i - 1 <= b.n + (1-1) by XCMPLX_1:29; hence bij.k <= b.k by A82,A83,A84,SCMFSA_7:3; end; hence bij.k <= b.k; suppose A85: not k in n+1; dom bij = n+1 by PBOOLE:def 3; then A86: bij.k = 0 by A85,FUNCT_1:def 4; dom b = n+1 by PBOOLE:def 3; hence bij.k <= b.k by A85,A86,FUNCT_1:def 4; end; then bij divides b by POLYNOM1:def 13; then bij in rng divisors b by Th7; then consider k being set such that A87: k in dom divisors b & bij = (divisors b).k by FUNCT_1:def 5; A88: dom p = dom u by A60,FUNCT_2:def 1; A89: dom u = dom decomp b by A23,FINSEQ_3:31 .= dom divisors b by POLYNOM1:def 19; k is Nat & bij = (divisors b).k & j in dom (divisors bn) & (divisors bn).j = bij|n by A74,A75,A76,A87,Def1; then A90: bij.n+1 in dom s & j in dom (s.(bij.n+1)) & p.k = (Sum Card (s|(bij.n+1-'1))) + j by A34,A87,A89; A91: 1 <= i & i <= b.n+1 by A6,A13,A74,FINSEQ_3:27; bij.n = i-'1 by Def1; then bij.n+1= i by A91,AMI_5:4; hence n1' in rng p by A74,A87,A88,A89,A90,FUNCT_1:def 5; end; then A92: rng p = dom t by XBOOLE_0:def 10; A93: dom p = dom u by A60,FUNCT_2:def 1; A94: len u = Card dom u by PRE_CIRC:21 .= Card (p qua set) by A93,PRE_CIRC:21 .= Card dom t by A72,A92,POLYNOM1:7 .= len t by PRE_CIRC:21; then A95: dom u = dom t by FINSEQ_3:31; then p is Permutation of dom u by A72,A92,FUNCT_2:83; hence Pxy.b' = PxPy.b' by A22,A23,A35,A94,A95,RLVECT_2:8; end; hence P.(x'*y') = (P.x')*(P.y') by FUNCT_2:18; end; end; cluster upm (n,R) -> unity-preserving; coherence proof set PRPNR = Polynom-Ring (Polynom-Ring(n,R)); set PN1R = Polynom-Ring(n+1,R); set PNR = Polynom-Ring(n,R); set CPN1R = the carrier of PN1R; set P = upm (n,R); reconsider p1 = 1_ PRPNR as Polynomial of PNR by POLYNOM3:def 12; reconsider p1' = 1_ PN1R as (Polynomial of n+1, R) by POLYNOM1:def 27; P.(1_ PRPNR) in CPN1R; then reconsider p3 = P.p1 as (Polynomial of n+1, R) by POLYNOM1:def 27; now let x be set; assume x in Bags (n+1); then reconsider b = x as Element of Bags (n+1); reconsider p2 = p1.(b.n) as Polynomial of n, R by POLYNOM1:def 27; A96: p3.b = p2.(b|n) by Def6; now per cases; suppose A97: b|n = EmptyBag(n) & b.n = 0; then A98: b = (EmptyBag n) bag_extend 0 by Def1.=EmptyBag (n+1) by Th6 ; p2 = (1_. (PNR)).0 by A97,POLYNOM3:def 12 .= 1_ (PNR) by POLYNOM3:31 .= 1_ (n,R) by POLYNOM1:def 27; hence p3.b = 1.R by A96,A97,POLYNOM1:84 .= 1_ (n+1,R).b by A98,POLYNOM1:84 .= p1'.b by POLYNOM1:def 27; suppose A99: b|n <> EmptyBag(n) or b.n <> 0; then b <> (EmptyBag n) bag_extend 0 by Def1; then A100: b <> EmptyBag (n+1) by Th6; now A101: p2 = (1_. (PNR)).(b.n) by POLYNOM3:def 12; n < n+1 by NAT_1:38; then A102: b|n is bag of n by Th3; per cases; suppose A103: b.n = 0; then p2 = 1_ (PNR) by A101,POLYNOM3:31 .= 1_ (n,R) by POLYNOM1:def 27; hence p3.b = 0.R by A96,A99,A102,A103,POLYNOM1:84; suppose b.n <> 0; then p2 = 0.(PNR) by A101,POLYNOM3:31 .= 0_ (n, R) by POLYNOM1:def 27; hence p3.b = 0.R by A96,A102,POLYNOM1:81; end; hence p3.b = 1_ (n+1,R).b by A100,POLYNOM1:84 .= p1'.b by POLYNOM1:def 27; end; hence p3.x = p1'.x; end; then p1' = p3 by FUNCT_2:18; hence P is unity-preserving by ENDALG:def 8; end; cluster upm (n,R) -> one-to-one; coherence proof set PRPNR = Polynom-Ring (Polynom-Ring(n,R)); set PNR = Polynom-Ring(n,R); set P = upm (n,R); now let x',y' being Element of PRPNR; assume A104: P.x' = P.y'; reconsider x=x', y=y' as Polynomial of PNR by POLYNOM3:def 12; reconsider Py = P.y' as Polynomial of n+1,R by POLYNOM1:def 27; now let bn' be set; assume bn' in NAT; then reconsider bn = bn' as Nat; reconsider xbn=x.bn, ybn = y.bn as Polynomial of n,R by POLYNOM1:def 27; now let b' be set; assume b' in Bags n; then reconsider b = b' as bag of n by POLYNOM1:def 14; set bn1 = b bag_extend bn; A105: bn1|n = b & bn1.n = bn by Def1; then (xbn).b = Py.bn1 by A104,Def6 .= (ybn).b by A105,Def6; hence (xbn).b' = (ybn).b'; end; hence x.bn' = y.bn' by FUNCT_2:18; end; hence x'=y' by FUNCT_2:18; end; hence P is one-to-one by WAYBEL_1:def 1; end; end; definition let R be Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n be Nat; func mpu (n,R) -> map of Polynom-Ring (n+1,R), Polynom-Ring Polynom-Ring(n,R) means :Def7: for p1 being (Polynomial of n+1,R), p2 being (Polynomial of n, R), p3 being (Polynomial of Polynom-Ring (n, R)), i being Nat, b being bag of n st p3 = it.p1 & p2 = p3.i holds p2.b = p1.(b bag_extend i); existence proof set PRPNR = Polynom-Ring (Polynom-Ring(n,R)); set PN1R = Polynom-Ring(n+1,R); set PNR = Polynom-Ring(n,R); set CPRPNR = the carrier of PRPNR; set CPN1R = the carrier of PN1R; set CPNR = the carrier of PNR; set CR = the carrier of R; defpred P1[Element of CPN1R, Element of CPRPNR] means for p1 being (Polynomial of n+1,R), p2 being (Polynomial of n, R), p3 being (Polynomial of Polynom-Ring (n, R)), i being Nat, b being bag of n st p1 = $1 & p3 = $2 & p2 = p3.i holds p2.b = p1.(b bag_extend i); A1: now let x being Element of CPN1R; reconsider p1=x as Polynomial of n+1,R by POLYNOM1:def 27; defpred P2[Nat, Element of CPNR] means for p2 being (Polynomial of n, R), b being bag of n st p2 = $2 holds p2.b = p1.(b bag_extend $1); A2: now let i being Nat; deffunc F(Element of Bags n)=p1.($1 bag_extend i); consider p2 being Function of Bags n,CR such that A3: for b being Element of Bags n holds p2.b = F(b) from LambdaD; reconsider p2 as Function of Bags n, R ; reconsider p2 as Series of n, R ; now per cases; suppose A4: Support p1 = {}; now assume Support p2 <> {}; then consider b being set such that A5: b in Support p2 by XBOOLE_0:def 1; reconsider b as Element of Bags n by A5; p2.b <> 0.R by A5,POLYNOM1:def 9; then p1.(b bag_extend i) <> 0.R by A3; hence Support p1 <> {} by POLYNOM1:def 9; end; hence Support p2 is finite by A4; suppose Support p2 = {}; hence Support p2 is finite; suppose A6: Support p1 <> {} & Support p2 <> {}; then reconsider Support_p1 = Support p1 as non empty Subset of Bags (n+1); reconsider Support_p2 = Support p2 as non empty Subset of Bags n by A6; defpred P[Element of Support_p2,set] means $2 = $1 bag_extend i; A7: now let x being Element of Support_p2; A8: x is Element of Bags n by POLYNOM1:def 14; x in Support p2; then p2.x <> 0.R by POLYNOM1:def 9; then p1.(x bag_extend i) <> 0.R by A3,A8; then x bag_extend i in Support p1 by POLYNOM1:def 9; hence ex y being Element of Support_p1 st P[x,y]; end; consider f being Function of Support_p2,Support_p1 such that A9: for x being Element of Support_p2 holds P[x,f.x] from FuncExD(A7); A10: dom f = Support_p2 by FUNCT_2:def 1; now let x1,x2 be set; assume A11: x1 in dom f & x2 in dom f & f.x1 = f.x2; then reconsider x1'=x1, x2'=x2 as Element of Bags n by A10 ; A12: x1' bag_extend i = f.x1 by A9,A11 .= x2' bag_extend i by A9,A11; x1' = (x1' bag_extend i)|n by Def1 .= x2' by A12, Def1 ; hence x1 = x2; end; then A13: f is one-to-one by FUNCT_1:def 8; rng f c= Support_p1 ; then Card Support_p2 <=` Card Support_p1 by A10,A13,CARD_1: 26; hence Support p2 is finite by CARD_2:68; end; then p2 is finite-Support by POLYNOM1:def 10; then reconsider p2'=p2 as Element of CPNR by POLYNOM1:def 27; take p2'; now let p2'' being (Polynomial of n, R), b being bag of n; assume A14: p2'' = p2'; b is Element of Bags n by POLYNOM1:def 14 ; hence p2''.b = p1.(b bag_extend i) by A3,A14; end; hence P2[i,p2']; end; consider p3 being Function of NAT,CPNR such that A15: for x being Nat holds P2[x,p3.x] from FuncExD(A2); reconsider p3 as sequence of PNR by NORMSP_1:def 3; now per cases; suppose A16: Support p1 = {}; now let i being Nat; assume i >= 0; reconsider p2 = p3.i as Polynomial of n, R by POLYNOM1:def 27; A17: dom ((Bags n) --> 0.R) = Bags n by FUNCOP_1:19; A18: dom (p2) = Bags n by FUNCT_2:def 1; now let x be set; assume x in Bags n; then reconsider x'=x as Element of Bags n; p1.(x' bag_extend i) = 0.R by A16,POLYNOM1:def 9; then p2.x' = 0.R by A15; hence p2.x = ((Bags n) --> 0.R).x by FUNCOP_1:13; end; then p2 = (Bags n) --> 0.R by A17,A18,FUNCT_1:9; hence p3.i = 0_(n,R) by POLYNOM1:def 24 .= 0.PNR by POLYNOM1:def 27 ; end; hence p3 is finite-Support by ALGSEQ_1:def 2; suppose Support p1 <> {}; then reconsider Support_p1 = Support p1 as finite non empty Subset of Bags (n+1); deffunc F(Element of Bags (n+1))=$1.n; consider f being Function of Bags (n+1), NAT such that A19: for x being Element of Bags (n+1) holds f.x = F(x) from LambdaD; reconsider j = max (f .: Support_p1) as Nat by ORDINAL2:def 21; now let i being Nat; assume A20: i >= j+1; reconsider p2 = p3.i as Polynomial of n, R by POLYNOM1:def 27; A21: dom ((Bags n) --> 0.R) = Bags n by FUNCOP_1:19; A22: dom (p2) = Bags n by FUNCT_2:def 1; now let x be set; assume x in Bags n; then reconsider x'=x as Element of Bags n; i > j by A20,NAT_1:38; then A23: not i in f.:Support_p1 by PRE_CIRC:def 1; f.(x' bag_extend i) = (x' bag_extend i).n by A19 .= i by Def1; then not x' bag_extend i in Support_p1 by A23,FUNCT_2:43; then p1.(x' bag_extend i) = 0.R by POLYNOM1:def 9; then p2.x' = 0.R by A15; hence p2.x = ((Bags n) --> 0.R).x by FUNCOP_1:13; end; then p2 = (Bags n) --> 0.R by A21,A22,FUNCT_1:9; hence p3.i = 0_(n,R) by POLYNOM1:def 24 .= 0.PNR by POLYNOM1:def 27 ; end; hence p3 is finite-Support by ALGSEQ_1:def 2; end; then reconsider y=p3 as Element of CPRPNR by POLYNOM3:def 12; take y; thus P1[x,y] by A15; end; consider P being Function of CPN1R,CPRPNR such that A24: for x being Element of CPN1R holds P1[x,P.x] from FuncExD(A1); reconsider P as map of PN1R,PRPNR; take P; now let p1 being (Polynomial of n+1,R), p2 being (Polynomial of n, R), p3 being (Polynomial of Polynom-Ring (n, R)), i being Nat, b being bag of n; assume A25: p3 = P.p1 & p2 = p3.i; p1 in CPN1R by POLYNOM1:def 27; hence p2.b = p1.(b bag_extend i) by A24,A25; end; hence thesis; end; uniqueness proof set PRPNR = Polynom-Ring (Polynom-Ring(n,R)); set PN1R = Polynom-Ring(n+1,R); set PNR = Polynom-Ring(n,R); set CPN1R = the carrier of PN1R; let A,B be map of PN1R,PRPNR; assume A26: for p1 being (Polynomial of n+1,R), p2 being (Polynomial of n, R), p3 being (Polynomial of Polynom-Ring (n, R)), i being Nat, b being bag of n st p3 = A.p1 & p2 = p3.i holds p2.b = p1.(b bag_extend i); assume A27: for p1 being (Polynomial of n+1,R), p2 being (Polynomial of n, R), p3 being (Polynomial of Polynom-Ring (n, R)), i being Nat, b being bag of n st p3 = B.p1 & p2 = p3.i holds p2.b = p1.(b bag_extend i); now let x be set; assume A28: x in CPN1R; then reconsider x''=x as Element of CPN1R; reconsider x'=x as Polynomial of n+1, R by A28,POLYNOM1:def 27; reconsider Ax=A.x'',Bx=B.x'' as Polynomial of PNR by POLYNOM3:def 12; now let i be set; assume i in NAT; then reconsider i'=i as Nat; reconsider Axi=Ax.i', Bxi=Bx.i' as Polynomial of n, R by POLYNOM1:def 27; now let b be set; assume b in Bags n; then reconsider b'=b as bag of n by POLYNOM1:def 14; thus Axi.b = x'.(b' bag_extend i') by A26 .= Bxi.b by A27; end; hence Ax.i = Bx.i by FUNCT_2:18; end; hence A.x=B.x by FUNCT_2:18; end; hence A=B by FUNCT_2:18; end; end; theorem Th30: for R being Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n being Nat, p being Element of Polynom-Ring (n+1,R) holds upm(n,R).(mpu(n,R).p) = p proof let R being Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n being Nat, p being Element of Polynom-Ring (n+1,R); set PNR = Polynom-Ring(n,R); reconsider p'=p as Polynomial of (n+1), R by POLYNOM1:def 27; reconsider upm_mpu_p = upm(n,R).(mpu(n,R).p) as Polynomial of (n+1), R by POLYNOM1:def 27; reconsider mpu_p = (mpu(n,R).p) as Polynomial of PNR by POLYNOM3:def 12; now let b' be set; assume b' in Bags (n+1); then reconsider b=b' as Element of Bags (n+1); reconsider mpu_p_bn = mpu_p.(b.n) as Polynomial of n, R by POLYNOM1:def 27; n < n+1 by NAT_1:38; then reconsider bn = (b|n) as bag of n by Th3; A1: b = bn bag_extend b.n by Def1; thus upm_mpu_p.b' = mpu_p_bn.bn by Def6 .= p'.b' by A1,Def7; end; hence upm(n,R).(mpu(n,R).p) = p by FUNCT_2:18; end; theorem Th31: for R being Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n being Nat ex P being map of Polynom-Ring (Polynom-Ring(n,R)),Polynom-Ring(n+1,R) st P is RingIsomorphism proof let R be Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative non trivial (non empty doubleLoopStr), n being Nat; set PN1R = Polynom-Ring(n+1,R); set CPRPNR = the carrier of Polynom-Ring (Polynom-Ring(n,R)); set CPN1R = the carrier of PN1R; set P = upm (n,R); A1: P is RingHomomorphism by QUOFIELD:def 21; now let p be set; assume p in CPN1R; then reconsider p' = p as Element of CPN1R; A2: dom P = CPRPNR by FUNCT_2:def 1; P.(mpu(n,R).p') = p' by Th30; hence p in rng P by A2,FUNCT_1:def 5; end; then CPN1R c= rng P by TARSKI:def 3; then rng P = CPN1R by XBOOLE_0:def 10; then A3: P is RingEpimorphism by A1,QUOFIELD:def 22; P is RingMonomorphism by A1,QUOFIELD:def 23; then P is RingIsomorphism by A3,QUOFIELD:def 24; hence thesis; end; begin :: Hilbert basis theorem definition :: Hilbert Basis Theorem let R be Noetherian Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative (non empty doubleLoopStr); cluster Polynom-Ring R -> Noetherian; coherence proof set PR = Polynom-Ring R; set cPR = the carrier of PR; set cR = the carrier of R; now assume PR is non Noetherian; then consider I being Ideal of PR such that A1: I is non finitely_generated by IDEAL_1:def 27; defpred P1[set,set,set] means ($2 is non empty finite Subset of I) implies (ex A,B being non empty Subset of cPR st A = $2 & B = I\(A-Ideal) & ex r being Element of cPR st r in minlen(B) & $3 = $2 \/ {r}); A2: now let n be Nat, x be Element of bool cPR; per cases; suppose not (x is non empty finite Subset of I); hence ex y be Element of bool cPR st P1[n,x,y]; suppose A3: x is non empty finite Subset of I; then reconsider x'=x as non empty Subset of cPR; set B = I\(x' -Ideal); now assume B = {}; then A4: I c= x'-Ideal by XBOOLE_1:37; x'-Ideal c= I-Ideal by A3,IDEAL_1:57; then x'-Ideal c= I by IDEAL_1:44; then x'-Ideal = I by A4,XBOOLE_0 :def 10; hence contradiction by A1,A3,IDEAL_1:def 26; end; then reconsider B as non empty Subset of cPR; A5: minlen(B) c= cPR by XBOOLE_1:1; consider r being set such that A6: r in minlen (B) by XBOOLE_0:def 1; reconsider r as Element of cPR by A5,A6; P1[n,x,x' \/ {r}] by A6; hence ex y be Element of bool cPR st P1[n,x,y]; end; consider F be Function of NAT,bool cPR such that A7: F.0 = {0.PR} & for n be Element of NAT holds P1[n,F.n,F.(n+1)] from RecExD(A2); defpred P[Nat] means F.$1 is non empty finite Subset of I; F.0 c= I proof let x be set; assume x in F.0; then x = 0.PR by A7,TARSKI:def 1; hence x in I by IDEAL_1:2; end; then A8: P[0] by A7; A9: now let n be Nat; assume P[n]; then reconsider Fn=F.n as non empty finite Subset of I; consider A,B being non empty Subset of cPR such that A10: A = Fn & B = I\(A-Ideal) and A11: ex r being Element of cPR st r in minlen(B) & F.(n+1)= Fn \/ {r} by A7; consider r being Element of cPR such that A12: r in minlen(B) & F.(n+1) = Fn \/ {r} by A11; r in I by A10,A12, XBOOLE_0:def 4; then {r} c= I by ZFMISC_1:37; hence P[n+1] by A12,XBOOLE_1:8; end; A13: for n being Nat holds P[n] from Ind(A8,A9); A14: for i,j being Nat st i <= j holds F.i c= F.j proof let i,j be Nat; assume i<=j; then consider m being Nat such that A15: j = i+m by NAT_1:28; defpred P[Nat] means F.i c= F.(i+$1); A16: P[0]; A17: for m being Nat st P[m] holds P[m+1] proof let m be Nat; assume A18: F.i c= F.(i+m); F.(i+m) is non empty finite Subset of I by A13; then consider A,B being non empty Subset of cPR such that A = F.(i+m) & B = I\(A-Ideal) and A19: ex r being Element of cPR st r in minlen(B) & F.((i+m)+1) = F.(i+m) \/ {r} by A7; consider r being Element of cPR such that A20: r in minlen(B) & F.((i+m)+1) = F.(i+m) \/ {r} by A19; F.(i+m) c= F.((i+m)+1) by A20,XBOOLE_1:7; then F.(i+m) c= F.(i+(m+1)) by XCMPLX_1:1; hence F.i c= F.(i+(m+1)) by A18,XBOOLE_1:1; end; for m being Nat holds P[m] from Ind(A16,A17); hence F.i c= F.j by A15; end; defpred P2[set,set] means ex n being Nat, A,B being non empty Subset of cPR st A = F.n & B = I\(A-Ideal) & n = $1 & F.(n+1) = F.n \/ {$2} & $2 in minlen(B); A21: now let x be Nat; F.x is non empty finite Subset of I by A13; then consider A,B being non empty Subset of cPR such that A22: A = F.x & B = I\(A-Ideal) and A23: ex r being Element of cPR st r in minlen(B)&F.(x+1)=F.x \/ {r} by A7; thus ex y being Element of cPR st P2[x,y] by A22,A23; end; consider f being Function of NAT, cPR such that A24: for x being Nat holds P2[x,f.x] from FuncExD(A21); A25: for i being Nat holds f.i <> 0.PR proof let i be Nat; consider n being Nat, A,B being non empty Subset of cPR such that A26: A = F.n & B = I\(A-Ideal) & n = i & F.(n+1) = F.n \/ {f.i} & f.i in minlen(B) by A24; F.n c= A-Ideal by A26,IDEAL_1:def 15; then A27: not f.i in F.n by A26,XBOOLE_0:def 4; 0 <= n by NAT_1:18; then A28: F.0 c=F.n by A14; 0.PR in F.0 by A7,TARSKI:def 1; hence thesis by A27,A28; end; A29: for i,j being Nat, fi, fj being Polynomial of R st i <= j & fi = f.i & fj = f.j holds len fi <= len fj proof let i,j be Nat, fi, fj be Polynomial of R; assume A30: i <= j & fi = f.i & fj = f.j; then consider k being Nat such that A31: j = i + k by NAT_1:28; defpred P[Nat] means for fk being Polynomial of R st fk=f.(i+$1) holds len fi <= len fk; A32: P[0] by A30; A33: now let k be Nat; assume A34: P[k]; now let fk1 be Polynomial of R; assume A35: fk1=f.(i+(k+1)); reconsider fk = f.(i+k) as Polynomial of R by POLYNOM3:def 12; A36: len fi <= len fk by A34; consider n being Nat, A,B being non empty Subset of cPR such that A37: A = F.n & B = I\(A-Ideal) & n = i+k & F.(n+1) = F.n \/ {f.(i+k)} & f.(i+k) in minlen(B) by A24; consider n' being Nat, A',B' being non empty Subset of cPR such that A38: A' = F.n' & B' = I\(A'-Ideal) & n' = i+(k+1) & F.(n'+1) = F.n' \/ {f.(i+(k+1))} & f.(i+(k+1)) in minlen(B') by A24; i+(k+1) = (i+k)+1 by XCMPLX_1:1; then i+k < i+(k+1) by NAT_1:38; then F.(i+k) c= F.(i+(k+1)) by A14; then A-Ideal c= A'-Ideal by A37,A38,IDEAL_1:57; then A39: not f.(i+(k+1)) in A-Ideal by A38,XBOOLE_0:def 4; f.(i+(k+1)) in I by A38,XBOOLE_0:def 4; then f.(i+(k+1)) in B by A37,A39,XBOOLE_0:def 4; then len fk <= len fk1 by A35,A37,Th17; hence len fi <= len fk1 by A36,AXIOMS:22; end; hence P[k+1]; end; for k being Nat holds P[k] from Ind(A32,A33); hence len fi <= len fj by A30,A31; end; defpred P3[set,set] means ex n being Nat, A being Polynomial of R st n = $1 & A = f.n & $2 = A.(len A -' 1); A40: now let x be Nat; reconsider fx=f.x as Polynomial of R by POLYNOM3:def 12; fx.(len fx -' 1) is Element of cR; hence ex y being Element of cR st P3[x,y]; end; consider a being Function of NAT, cR such that A41: for x being Nat holds P3[x,a.x] from FuncExD(A40); reconsider a as sequence of R by NORMSP_1:def 3; for B being non empty Subset of cR ex C being non empty finite Subset of cR st C c= B & C-Ideal = B-Ideal by IDEAL_1:99; then consider m being Nat such that A42: a.(m+1) in (rng (a|Segm(m+1)))-Ideal by IDEAL_1:100; consider lc being LinearCombination of (rng (a|Segm(m+1))) such that A43: a.(m+1) = Sum lc by A42,IDEAL_1:60; reconsider fm1 = f.(m+1) as Polynomial of R by POLYNOM3:def 12; A44: now let i be Nat, fi be Polynomial of R; assume fi = f.i; then fi <> 0.PR by A25; then fi <> 0_.R by POLYNOM3:def 12; then len fi <> 0 by POLYNOM4:8; then len fi > 0 by NAT_1:19; then len fi >= 0+1 by NAT_1:38; hence len fi-1 >= 0 by REAL_1:84; end; defpred P4[set,set] means (ex u,v,w being Element of cR st $1 = u*v*w & v in rng (a|Segm(m+1))) implies ex x,y,z being Element of cPR, p being Polynomial of R st $2 = p & p = (x*y)*z & $1 = p.(len fm1 -' 1) & len p <= len fm1 & y in F.(m+1); A45: for e being set st e in cR ex d being set st d in cPR & P4[e,d] proof let e be set; assume e in cR; per cases; suppose ex u,v,w being Element of cR st e= u*v*w & v in rng (a|Segm(m+1)); then consider u,b',w being Element of cR such that A46: e = u*b'*w and A47: b' in rng (a|Segm(m+1)); set a' = u; set c' = w; consider n being set such that A48: n in dom (a|Segm(m+1)) & b' = (a|Segm(m+1)).n by A47,FUNCT_1:def 5; A49: dom (a|Segm(m+1)) = dom a /\ Segm(m+1) by FUNCT_1:68 .= NAT /\ Segm(m+1) by FUNCT_2:def 1 .= Segm(m+1) by XBOOLE_1:28; reconsider n as Nat by A48; m >= 0 by NAT_1:18; then m+1 > 0 by NAT_1:38; then A50: n < m+1 by A48,A49,GR_CY_1:10; set y = f.n; reconsider y'=y as Polynomial of R by POLYNOM3:def 12; set x' = monomial(a',len fm1 -' len y'); set z' = monomial(c',0); reconsider x=x',z=z' as Element of cPR by POLYNOM3:def 12; set p = (x*y)*z; A51: x*y = x'*'y' by POLYNOM3:def 12; then A52: p = (x'*'y')*'z' by POLYNOM3:def 12; A53: b' = a.n by A48,FUNCT_1:70; consider n' being Nat, A being Polynomial of R such that A54: n' = n & A = f.n' & a.n = A.(len A -' 1) by A41; reconsider p as Polynomial of R by POLYNOM3:def 12; len y' <= len fm1 by A29,A50; then len y' - len y' <= len fm1 - len y' by REAL_1:49; then 0 <= len fm1 - len y' by XCMPLX_1:14; then A55: len fm1 -' len y' = len fm1 - len y' by BINARITH:def 3; A56: len y' -1 >= 0 by A44; len fm1 - 1 >= 0 by A44; then len fm1 -' 1 = len fm1 + 0 - 1 by BINARITH:def 3 .= len fm1 + (len y' - len y') - 1 by XCMPLX_1:14 .= len fm1 + (len y' + -len y') -1 by XCMPLX_0:def 8 .= len fm1 + - len y' + len y' - 1 by XCMPLX_1:1 .= len fm1 - len y' + len y' - 1 by XCMPLX_0:def 8 .= (len fm1 - len y') + (len y' -1) by XCMPLX_1:29 .= (len y' -' 1) + (len fm1 -' len y') by A55,A56,BINARITH:def 3; then A57: (x'*'y').(len fm1 -'1) = a' * b' by A53,A54,Th19; len fm1 -' 1 = (len fm1 -' 1) + 0; then A58: (a'*b')*c' = p.(len fm1 -' 1) by A52,A57,Th20; len x' <= len fm1 - len y' +1 by A55,Th18; then len x' <= len fm1 - (len y' -1 ) by XCMPLX_1:37; then len x' + (len y'-1) <= len fm1-(len y'-1)+(len y'-1) by AXIOMS: 24; then len x' + (len y'-1) <= len fm1-((len y'-1)-(len y'-1)) by XCMPLX_1:37; then len x' + (len y'-1) <= len fm1-0 by XCMPLX_1:14; then A59: len x' + len y' -1 <= len fm1 by XCMPLX_1:29; len x' >= 0 by NAT_1:18; then 0+0 <= (len y' - 1)+len x' by A56,REAL_1:55; then 0 <= len y' + -1 + len x' by XCMPLX_0:def 8; then 0 <= len y' + len x' + -1 by XCMPLX_1:1; then A60: 0 <= len x' + len y' -1 by XCMPLX_0:def 8; len (x'*'y') <= len x' + len y' -' 1 by Th21; then len (x'*'y') <= len x' + len y' - 1 by A60,BINARITH:def 3; then A61: len (x'*'y') <= len fm1 by A59,AXIOMS:22; len z' <= 0+1 by Th18; then len (x'*'y') + len z' <= len fm1 + 1 by A61,REAL_1:55; then A62: len(x'*'y')+len z'-'1 <= len fm1+1-'1 by JORDAN3:5; len fm1+(1-1) >= 0+(1-1) by NAT_1:18; then A63: len fm1+1-1 >= (1-1) by XCMPLX_1:29; len ((x'*'y')*'z') <= len (x'*'y') + len z' -' 1 by Th21; then len ((x'*'y')*'z') <= len fm1 +1 -' 1 by A62,AXIOMS:22; then len ((x'*'y')*'z') <= len fm1 +1 -1 by A63,BINARITH:def 3; then len ((x'*'y')*'z') <= len fm1+(1-1) by XCMPLX_1:29; then A64: len p <= len fm1+0 by A51,POLYNOM3:def 12; n+1 <= m+1 by A50,NAT_1:38; then A65: F.(n+1) c= F.(m+1) by A14; consider n' being Nat, A,B being non empty Subset of cPR such that A66: A = F.n' & B = I\(A-Ideal) & n' = n & F.(n'+1) = F.n' \/ {f.n} & f.n in minlen(B) by A24; {y} c= F.(n+1) by A66,XBOOLE_1:7; then y in F.(n+1) by ZFMISC_1:37 ; hence ex u being set st u in cPR & P4[e,u] by A46,A58,A64,A65; suppose not ex u,v,w being Element of cR st e= u*v*w & v in rng (a|Segm(m+1)); hence ex u being set st u in cPR & P4[e,u]; end; consider LCT being Function of cR, cPR such that A67: for e being set st e in cR holds P4[e,LCT.e] from FuncEx1(A45); reconsider FM1 = F.(m+1) as non empty Subset of cPR by A13; set raSm1 = rng(a|Segm(m+1)); A68: for lc being LinearCombination of raSm1 ex LC being LinearCombination of FM1 st LC = LCT * lc & len lc = len LC proof let lc be LinearCombination of raSm1; dom LCT = cR by FUNCT_2:def 1; then rng lc c= dom LCT; then A69: dom lc = dom (LCT*lc) by RELAT_1:46; set LC = LCT * lc; A70: len lc = len LC by A69,FINSEQ_3:31; LC is LinearCombination of FM1 proof let i be set such that A71: i in dom LC; consider u,v being Element of R, a being Element of raSm1 such that A72: lc/.i = u*a*v by A69,A71,IDEAL_1:def 9; A73: lc/.i = lc.i by A69,A71,FINSEQ_4:def 4; consider x,y,z being Element of cPR, p being Polynomial of R such that A74: LCT.(lc/.i) = p & p = (x*y)*z & (u*a)*v = p.(len fm1 -' 1) & len p <= len fm1 & y in F.(m+1) by A67,A72; reconsider x, z as Element of PR; reconsider y as Element of FM1 by A74; LC/.i = (LCT*lc).i by A71,FINSEQ_4:def 4 .= x*y*z by A69,A71,A73,A74,FUNCT_1:23; hence ex x,z being Element of PR, y being Element of FM1 st LC/.i = x*y*z; end; then reconsider LC as LinearCombination of FM1; LC = LC; hence ex LC being LinearCombination of FM1 st LC = LCT * lc & len lc = len LC by A70; end; for lc being LinearCombination of raSm1 ex LC being LinearCombination of FM1, sLC being Polynomial of R st LC = LCT*lc & sLC = Sum LC & sLC.(len fm1 -' 1) = Sum lc & len sLC <= len fm1 proof defpred P5[Nat] means for lc being LinearCombination of raSm1 st len lc <= $1 holds ex LC being LinearCombination of FM1, sLC being Polynomial of R st LC = LCT*lc & sLC = Sum LC & sLC.(len fm1 -' 1) = Sum lc & len sLC <= len fm1; A75: P5[0] proof let lc be LinearCombination of (raSm1); assume len lc <= 0; then A76: len lc = 0 by NAT_1:18; consider LC being LinearCombination of FM1 such that A77: LC = LCT * lc & len lc = len LC by A68; take LC, p = 0_.(R); thus LC = LCT * lc by A77; A78: lc = <*>cR by A76,FINSEQ_1:25; LC = <*>cPR by A76,A77,FINSEQ_1: 25; then Sum LC = 0.PR by RLVECT_1:60 .= p by POLYNOM3:def 12; hence p = Sum LC; thus p.(len fm1 -' 1) = 0.R by POLYNOM3:28 .= Sum lc by A78,RLVECT_1:60; len p = 0 by POLYNOM4:6; hence len p <= len fm1 by NAT_1:18; end; A79: for k being Nat st P5[k] holds P5[k+1] proof let k be Nat; assume A80: P5[k]; thus P5[k+1] proof let lc be LinearCombination of (raSm1); assume A81: len lc <= k+1; per cases; suppose len lc <= k; hence thesis by A80; suppose len lc > k; then len lc >= k+1 by NAT_1:38; then A82: len lc = k+1 by A81,AXIOMS:21; thus thesis proof per cases by NAT_1:19; suppose A83: k = 0; then dom lc = {1} by A82,FINSEQ_1:4,def 3; then A84: 1 in dom lc by TARSKI:def 1; A85: lc = <*lc.1*> by A82,A83,FINSEQ_1:57; consider u,w being Element of R, v being Element of raSm1 such that A86: lc/.1 = u*v*w by A84,IDEAL_1:def 9; A87: lc.1 = lc/.1 by A84,FINSEQ_4:def 4; then consider x,y,z being Element of cPR, p being Polynomial of R such that A88: LCT.(lc.1) = p & p = (x*y)*z & (u*v)*w = p.(len fm1 -' 1) & len p <= len fm1 & y in F.(m+1) by A67,A86; consider LC being LinearCombination of FM1 such that A89: LC = LCT*lc & len LC = len lc by A68; A90: LC = <* LCT.(u*v*w) *> by A85,A86,A87,A89,FINSEQ_2:39; A91: Sum lc = p.(len fm1 -' 1) by A85,A86,A87,A88,RLVECT_1: 61; Sum LC = p by A86,A87,A88,A90,RLVECT_1:61; hence thesis by A88,A89,A91; suppose A92: k > 0; then len lc > 0+1 by A82,REAL_1:53 ; then len lc <> 0; then lc is non empty by FINSEQ_1:25 ; then consider p being LinearCombination of raSm1, e being Element of cR such that A93: lc = p^<*e*> and A94: <*e*> is LinearCombination of raSm1 by IDEAL_1:32; len lc = len p + len <* e *> by A93,FINSEQ_1:35 .= len p + 1 by FINSEQ_1:56; then len p = k by A82,XCMPLX_1:2; then consider LCp being LinearCombination of FM1, sLCp being Polynomial of R such that A95: LCp = LCT*p & sLCp = Sum LCp & sLCp.(len fm1 -' 1) = Sum p & len sLCp <= len fm1 by A80; len <* e *> = 0+1 by FINSEQ_1:56; then len <*e*> <= k by A92,NAT_1:38; then consider LCe being LinearCombination of FM1, sLCe being Polynomial of R such that A96: LCe = LCT*<*e*> & sLCe = Sum LCe & sLCe.(len fm1 -' 1) = Sum <* e *> & len sLCe <= len fm1 by A80,A94; consider LC being LinearCombination of FM1 such that A97: LC = LCT*lc & len LC = len lc by A68; dom LCT = cR by FUNCT_2:def 1; then rng p \/ rng <* e *> c= dom LCT; then consider LCTp, LCTe being FinSequence such that A98: LCTp = LCT*p & LCTe = LCT*<*e*> & LCT*(p^<*e*>) = LCTp^LCTe by Th1; set sLC = sLCp + sLCe; A99: Sum LC = Sum LCp + Sum LCe by A93,A95,A96,A97,A98, RLVECT_1:58 .= sLC by A95,A96,POLYNOM3:def 12; A100: Sum lc = Sum p + e by A93,FVSUM_1:87 .= sLCp.(len fm1 -' 1) + sLCe.(len fm1 -' 1) by A95,A96,RLVECT_1:61 .= sLC.(len fm1 -' 1) by POLYNOM3:def 6; now per cases; suppose len sLCp < len sLCe; then len sLC <= len sLCe by POLYNOM4:9; hence len sLC <= len fm1 by A96,AXIOMS:22; suppose len sLCp >= len sLCe; then len sLC <= len sLCp by POLYNOM4:9; hence len sLC <= len fm1 by A95,AXIOMS:22; end; hence thesis by A97,A99,A100; end; end; end; A101: for k being Nat holds P5[k] from Ind(A75,A79); let lc be LinearCombination of (raSm1); consider n being Nat such that A102: n = len lc; thus thesis by A101,A102; end; then consider LC being LinearCombination of FM1, sLC being Polynomial of R such that A103: LC = LCT*lc & sLC = Sum LC & sLC.(len fm1 -' 1) = Sum lc & len sLC <= len fm1; set f'=fm1-sLC; A104: f' = fm1+(-sLC) by POLYNOM3:def 8; then A105: f'+sLC = fm1+(sLC+(-sLC)) by POLYNOM3:26 .= fm1+(sLC-sLC) by POLYNOM3:def 8 .= fm1+0_.R by POLYNOM3:30 .= fm1 by POLYNOM3:29; len (-sLC) <= len fm1 by A103,POLYNOM4:11; then A106: len f' <= len fm1 by A104,POLYNOM4:9; now assume A107: len f' = len fm1; len fm1 - 1 >= 0 by A44; then A108: (len fm1 -' 1) + 1 = (len fm1 - 1) + 1 by BINARITH:def 3 .= len fm1 - (1 - 1) by XCMPLX_1:37 .= len fm1; consider n being Nat, A being Polynomial of R such that A109: n = m+1 & A = f.n & a.(m+1) = A.(len A -' 1) by A41; f'.(len fm1 -' 1)= fm1.(len fm1 -' 1) - fm1.(len fm1 -' 1) by A43, A103,A109,POLYNOM3:27 .= 0.R by RLVECT_1:28; hence contradiction by A107,A108,ALGSEQ_1:25; end; then A110: len f' < len fm1 by A106,AXIOMS:21; A111: sLC in FM1-Ideal by A103,IDEAL_1:60; consider n being Nat, A,B being non empty Subset of cPR such that A112: A = F.n & B = I\(A-Ideal) & n = m+1 & F.(n+1) = F.n \/ {f.(m+1)} & f.(m+1) in minlen(B) by A24; A113: now assume A114: f' in FM1-Ideal; reconsider sLC as Element of cPR by POLYNOM3:def 12; reconsider f' as Element of cPR by POLYNOM3:def 12; f.(m+1) = f'+sLC by A105,POLYNOM3:def 12; then fm1 in FM1-Ideal by A111,A114,IDEAL_1:def 1; hence contradiction by A112,XBOOLE_0:def 4; end; f' in I proof FM1 is Subset of I by A13; then FM1-Ideal c= I-Ideal by IDEAL_1:57; then A115: FM1-Ideal c= I by IDEAL_1:44; reconsider sLC as Element of cPR by POLYNOM3:def 12; reconsider f' as Element of cPR by POLYNOM3:def 12; A116: f.(m+1) in I by A112,XBOOLE_0:def 4; f'=f.(m+1)-sLC by Th16; hence thesis by A111,A115,A116,IDEAL_1:15; end; then f' in I\(FM1-Ideal) by A113,XBOOLE_0:def 4; hence contradiction by A110,A112,Th17; end; hence PR is Noetherian; end; end; Lm1: for R being Noetherian Abelian add-associative right_zeroed right_complementable associative distributive well-unital commutative (non empty doubleLoopStr) holds Polynom-Ring R is Noetherian; canceled; theorem Th33: for R being Abelian add-associative right_zeroed right_complementable associative distributive well-unital non trivial commutative (non empty doubleLoopStr) st R is Noetherian for n being Nat holds Polynom-Ring (n,R) is Noetherian proof let R be Abelian add-associative right_zeroed right_complementable associative distributive well-unital non trivial commutative (non empty doubleLoopStr); assume A1: R is Noetherian; consider P being map of R, Polynom-Ring (0,R) such that A2: P is RingIsomorphism by Th28; defpred P[Nat] means Polynom-Ring($1,R) is Noetherian; A3: P[0] by A1,A2,Th27; A4: now let k be Nat such that A5: P[k]; consider P being map of Polynom-Ring(Polynom-Ring(k,R)), Polynom-Ring(k+1,R) such that A6: P is RingIsomorphism by Th31; Polynom-Ring (Polynom-Ring(k,R)) is Noetherian by A5,Lm1; hence P[k+1] by A6,Th27; end; thus for n being Nat holds P[n] from Ind(A3, A4); end; theorem Th34: for F being Field holds F is Noetherian proof let F be Field; let I be Ideal of F; per cases by IDEAL_1:22; suppose A1: I = {0.F}; reconsider s0F = {0.F} as finite non empty Subset of F; {0.F} = s0F-Ideal by IDEAL_1:47; hence I is finitely_generated by A1; suppose A2: I = the carrier of F; reconsider s1F = {1_ F} as finite non empty Subset of F; the carrier of F = s1F-Ideal by IDEAL_1:51; hence I is finitely_generated by A2; end; theorem for F being Field, n being Nat holds Polynom-Ring (n,F) is Noetherian proof let F be Field, n be Nat; F is Noetherian by Th34; hence Polynom-Ring (n,F) is Noetherian by Th33; end; theorem for R being Abelian right_zeroed add-associative right_complementable well-unital distributive associative commutative non trivial (non empty doubleLoopStr), X be infinite Ordinal holds Polynom-Ring (X,R) is non Noetherian proof let R be Abelian right_zeroed add-associative right_complementable well-unital distributive associative commutative non trivial (non empty doubleLoopStr), X be infinite Ordinal such that A1: Polynom-Ring (X,R) is Noetherian; set tcR = the carrier of R; set tcPR = the carrier of Polynom-Ring(X,R); A2: NAT c= X by CARD_4:8; set S = {1_1(n, R) where n is Element of X : n in NAT }; A3: S c= tcPR proof let x be set; assume x in S; then consider n being Element of X such that A4: x = 1_1(n,R) & n in NAT; thus x in tcPR by A4,POLYNOM1:def 27; end; 0 in NAT; then reconsider 0X = 0 as Element of X by A2; 1_1(0X,R) in S; then reconsider S as non empty Subset of tcPR by A3; consider C being non empty finite Subset of tcPR such that A5: C c= S and A6: C-Ideal = S-Ideal by A1,IDEAL_1:99; deffunc F(set)=$1; deffunc G(Element of X)=1_1($1,R); set CN = { F(n) where n is Element of X : G(n) in C }; A7: C is finite; A8: for d1,d2 being Element of X st G(d1)=G(d2) holds d1=d2 by Th14; A9: CN is finite from FinMono(A7,A8); consider c being Element of C; c in C; then c in S by A5; then consider cn being Element of X such that A10: c = 1_1(cn,R) & cn in NAT; reconsider cn as Nat by A10; A11: cn in CN by A10; CN c= NAT proof let x be set; assume x in CN; then consider n being Element of X such that A12: x = n & 1_1(n,R) in C; 1_1(n,R) in S by A5,A12; then consider m being Element of X such that A13: 1_1(n,R) = 1_1(m,R) & m in NAT; thus x in NAT by A12,A13,Th14; end; then reconsider CN as non empty finite Subset of NAT by A9,A11; reconsider mm = max CN as Nat by ORDINAL2:def 21; reconsider m1 = mm+1 as Nat; m1 in NAT; then reconsider m2 = m1 as Element of X by A2; 1_1(m2,R) in S & S c= S-Ideal by IDEAL_1:def 15; then consider lc being LinearCombination of C such that A14: 1_1(m2,R) = Sum lc by A6,IDEAL_1:60; A15: 1.R = 1_ R by POLYNOM2:3; reconsider ev = (X --> 0.R)+*(m2,1_ R) as Function of X, R; dom (X --> 0.R) = X by FUNCOP_1:19; then A16: ev.m2 = 1_ R by FUNCT_7:33; A17: Support(1_1(m2,R)) = {UnitBag m2} by Th13; A18: Polynom-Evaluation(X, R, ev).1_1(m2,R) = eval(1_1(m2,R), ev) by POLYNOM2:def 5 .= (1_1(m2,R).UnitBag m2)*eval(UnitBag m2,ev) by A17,POLYNOM2:21 .= 1.R *eval(UnitBag m2,ev) by Th12 .= 1.R * ev.m2 by Th11 .= 1_ R by A16,GROUP_1:def 4; tcR c= tcR; then reconsider cR = the carrier of R as non empty Subset of tcR; consider E be FinSequence of [:tcPR, tcPR, tcPR:] such that A19: E represents lc by IDEAL_1:35; set P = Polynom-Evaluation(X, R, ev); deffunc F(Nat)=(P.(E/.$1)`1)*(P.(E/.$1)`2)*(P.(E/.$1)`3); consider LC being FinSequence of the carrier of R such that A20: len LC = len lc and A21: for k being Nat st k in Seg len lc holds LC.k = F(k) from SeqLambdaD; now let i being set; assume A22: i in dom LC; then reconsider k = i as Nat; A23: k in Seg len lc by A20,A22,FINSEQ_1:def 3; reconsider u=(P.(E/.k)`1), v=(P.(E/.k)`3) as Element of R; reconsider a = (P.(E/.k)`2) as Element of cR; take u, v, a; thus LC/.i = LC.k by A22,FINSEQ_4:def 4 .= u*a*v by A21,A23; end; then reconsider LC as LinearCombination of cR by IDEAL_1:def 9; A24: now let i be Nat; assume A25: i in dom LC; then A26: i in dom lc by A20,FINSEQ_3:31; A27: i in Seg len lc by A20,A25,FINSEQ_1:def 3; reconsider y = (E/.i)`2 as Element of C by A19,A26,IDEAL_1:def 12; y in C; then y in S by A5; then consider n being Element of X such that A28: y = 1_1(n, R) & n in NAT; A29: n in CN by A28; now assume m2 in CN; then (max CN)+1 <= max CN by FRECHET2:51; hence contradiction by REAL_2:174; end; then A30: ev.n = (X --> 0.R).n by A29,FUNCT_7:34 .= 0.R by FUNCOP_1:13; A31: Support(1_1(n,R)) = {UnitBag n} by Th13; A32: P.1_1(n,R) = eval(1_1(n,R), ev) by POLYNOM2:def 5 .= (1_1(n,R).UnitBag n)*eval(UnitBag n,ev) by A31,POLYNOM2:21 .= 1.R *eval(UnitBag n,ev) by Th12 .= 1.R * ev.n by Th11 .= 0.R by A30,VECTSP_1:36; thus LC.i = (P.(E/.i)`1)*(P.(E/.i)`2)*(P.(E/.i)`3) by A21,A27 .= 0.R*(P.(E/.i)`3) by A28,A32,VECTSP_1:36 .= 0.R by VECTSP_1:36 ; end; now let k be set; assume A33: k in dom LC; then reconsider i = k as Nat; i in Seg len lc by A20,A33,FINSEQ_1:def 3; hence LC.k = (P.(E/.k)`1)*(P.(E/.k)`2)*(P.(E/.k)`3) by A21; end; then P.(Sum lc) = Sum LC by A19,A20,Th24 .=0.R by A24,POLYNOM3:1; hence contradiction by A14,A15,A18,POLYNOM1:27; end;