Copyright (c) 2000 Association of Mizar Users
environ vocabulary ORDERS_1, FUNCT_1, MATRIX_2, FINSET_1, SQUARE_1, FINSEQ_1, BOOLE, FUNCT_5, MCART_1, LATTICES, LATTICE3, RELAT_2, FINSUB_1, PARTFUN1, HEYTING1, TARSKI, RELAT_1, SUBSTLAT, NORMFORM, BINOP_1, FILTER_1, CAT_1, YELLOW_0, WELLORD1, HEYTING2, BHSP_3, HEYTING3; notation TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, NUMBERS, XCMPLX_0, XREAL_0, RELAT_1, FUNCT_1, ORDERS_1, NAT_1, FINSEQ_1, BINOP_1, FINSET_1, FINSUB_1, PARTFUN1, LATTICES, DOMAIN_1, STRUCT_0, SUBSTLAT, MCART_1, FUNCT_5, WELLORD1, YELLOW_0, ABIAN, PRE_CIRC, LATTICE3, HEYTING2; constructors NAT_1, SETWISEO, DOMAIN_1, ABIAN, INT_1, TOLER_1, PRE_CIRC, WAYBEL_1, HEYTING1, HEYTING2, YELLOW_4; clusters RELSET_1, LATTICES, FINSET_1, SUBSET_1, FINSUB_1, SUBSTLAT, PARTFUN1, STRUCT_0, LATTICE3, ABIAN, NAT_1, YELLOW_1, YELLOW_3, BINARITH, FINSEQ_1, YELLOW_0, XREAL_0, MEMBERED, PRE_CIRC, ORDINAL2; requirements SUBSET, BOOLE, NUMERALS, REAL, ARITHM; definitions TARSKI, LATTICE3, FUNCT_1, XBOOLE_0; theorems HEYTING2, ZFMISC_1, PARTFUN1, YELLOW_0, LATTICE3, TARSKI, CQC_THE1, ABIAN, NAT_1, AXIOMS, REAL_1, LATTICE5, FINSEQ_1, SCMFSA9A, FINSET_1, FRECHET2, MCART_1, FUNCT_5, WAYBEL26, ORDERS_1, YELLOW_5, PRE_CIRC, SUBSTLAT, FINSUB_1, WAYBEL15, LATTICES, GRFUNC_1, RELAT_1, REAL_2, SYSREL, BINOP_1, FUNCT_1, FUNCT_2, WELLORD1, XBOOLE_0, XBOOLE_1, XCMPLX_1, RLVECT_1, ORDINAL2; schemes LMOD_7, XBOOLE_0; begin :: Preliminaries scheme SSubsetUniq { R() -> RelStr, P[set] } : for A1, A2 being Subset of R() st (for x being set holds x in A1 iff P[x]) & (for x being set holds x in A2 iff P[x]) holds A1 = A2 proof let A1, A2 be Subset of R(); assume that A1: for x being set holds x in A1 iff P[x] and A2: for x being set holds x in A2 iff P[x]; thus A1 c= A2 proof let x be set; assume x in A1; then P[x] by A1; hence thesis by A2; end; let x be set; assume x in A2; then P[x] by A2; hence thesis by A1; end; Lm1: for A, x being set holds [:A, {x}:] is Function proof let A, x be set; set X = [:A, {x}:]; X is Function-like proof let y,y1,y2 be set; assume [y,y1] in X & [y,y2] in X; then y1 = x & y2 = x by ZFMISC_1:129; hence thesis; end; hence thesis by RELAT_1:6; end; definition let A, x be set; cluster [:A, {x}:] -> Function-like; coherence by Lm1; end; Lm2: 0 = 2 * 0 & 2 = 2 * 1; then Lm3: 0 is even & 2 is even by ABIAN:def 2; 1 = 0 + 1; then Lm4: 1 is odd by Lm2,SCMFSA9A:1; theorem Th1: for n being odd Nat holds 1 <= n proof let n be odd Nat; 0 < n by Lm3,NAT_1:19; then 0 + 1 <= n by NAT_1:38; hence thesis; end; theorem for X being finite non empty Subset of NAT holds max X in X by PRE_CIRC:def 1; theorem Th3: for X being finite non empty Subset of NAT holds ex n being Nat st X c= Seg n \/ {0} proof let X be finite non empty Subset of NAT; reconsider m = max X as Nat by ORDINAL2:def 21; take m; let x be set; assume A1: x in X; then reconsider n = x as Nat; A2: Seg m c= Seg m \/ {0} & {0} c= Seg m \/ {0} by XBOOLE_1:7; A3: n <= m by A1,FRECHET2:51; per cases by CQC_THE1:2; suppose 1 <= n; then n in Seg m by A3,FINSEQ_1:3; hence thesis by A2; suppose 0 = n; then n in {0} by TARSKI:def 1; hence thesis by A2; end; theorem for X being finite Subset of NAT holds ex k being odd Nat st not k in X proof let X be finite Subset of NAT; per cases; suppose A1: X is non empty; assume A2: for k being odd Nat holds k in X; consider n being Nat such that A3: X c= Seg n \/ {0} by A1,Th3; A4: not 2*n+1 in X proof assume A5: 2*n+1 in X; not 2*n+1 in {0} by TARSKI:def 1; then 2*n+1 in Seg n by A3,A5,XBOOLE_0:def 2; then A6: 2*n+1 <= n by FINSEQ_1:3; 1*n <= 2*n by NAT_1:20; hence thesis by A6,NAT_1:38; end; 2*n+1 is odd by SCMFSA9A:1; hence contradiction by A2,A4; suppose X is empty; hence thesis; end; theorem Th5: for k being Nat, X being finite non empty Subset of [:NAT,{k}:] holds ex n being non empty Nat st X c= [:Seg n \/ {0},{k}:] proof let k be Nat; let X be finite non empty Subset of [:NAT,{k}:]; reconsider pX = proj1 X as finite non empty Subset of NAT by FUNCT_5:13,WAYBEL26:40; reconsider mpX = max pX as Nat by ORDINAL2:def 21; reconsider m = mpX + 1 as non empty Nat; take m; let x be set; assume A1: x in X; then consider x1,x2 being set such that A2: x1 in NAT & x2 in {k} & x = [x1,x2] by ZFMISC_1:def 2; A3: x1 = x`1 by A2,MCART_1:7; reconsider n = x`1 as Nat by A2,MCART_1:7; A4: Seg m c= Seg m \/ {0} & {0} c= Seg m \/ {0} by XBOOLE_1:7; A5: max pX <= m by NAT_1:29; n in pX by A1,A2,A3,FUNCT_5:def 1; then n <= max pX by FRECHET2:51; then A6: n <= m by A5,AXIOMS:22; per cases by CQC_THE1:2; suppose 1 <= n; then n in Seg m by A6,FINSEQ_1:3; hence thesis by A2,A3,A4,ZFMISC_1:106; suppose 0 = n; then n in {0} by TARSKI:def 1; hence thesis by A2,A3,A4,ZFMISC_1:106; end; theorem Th6: for m being Nat, X being finite non empty Subset of [:NAT,{m}:] holds ex k being non empty Nat st not [2*k+1,m] in X proof let m be Nat; let X be finite non empty Subset of [:NAT,{m}:]; assume A1: for k being non empty Nat holds [2*k+1,m] in X; consider n being non empty Nat such that A2: X c= [:Seg n \/ {0},{m}:] by Th5; not [2*n+1,m] in X proof assume [2*n+1,m] in X; then A3: 2*n+1 in Seg n \/ {0} by A2,ZFMISC_1:106; not 2*n+1 in {0} by TARSKI:def 1; then 2*n+1 in Seg n by A3,XBOOLE_0:def 2; then A4: 2*n+1 <= n by FINSEQ_1:3; 1*n <= 2*n by NAT_1:20; hence thesis by A4,NAT_1:38; end; hence contradiction by A1; end; theorem for m being Nat, X being finite Subset of [:NAT,{m}:] ex k being Nat st for l being Nat st l >= k holds not [l,m] in X proof let m be Nat; let X be finite Subset of [:NAT,{m}:]; per cases; suppose X is non empty; then reconsider X' = X as finite non empty Subset of [:NAT,{m}:]; consider n being non empty Nat such that A1: X' c= [:Seg n \/ {0},{m}:] by Th5; take k = n+1; let l be Nat; assume A2: l >= k; assume [l,m] in X; then A3: l in Seg n \/ {0} by A1,ZFMISC_1:106; now per cases by A3,XBOOLE_0:def 2; suppose l in Seg n; then l <= n by FINSEQ_1:3; hence contradiction by A2,NAT_1:38; suppose l in {0}; then l = 0 by TARSKI:def 1; hence contradiction by A2,NAT_1:18; end; hence thesis; suppose A4: X is empty; consider k being Nat; for l being Nat st l >= k holds not [l,m] in X by A4; hence thesis; end; theorem for L being upper-bounded Lattice holds Top L = Top LattPOSet L proof let L be upper-bounded Lattice; set x = %Top LattPOSet L; A1: %Top LattPOSet L = Top LattPOSet L by LATTICE3:def 4; now let a be Element of L; A2: x% = x by LATTICE3:def 3; a% <= Top LattPOSet L by YELLOW_0:45; then a% <= x% by A2,LATTICE3:def 4; then a [= x by LATTICE3:7; hence x"\/"a = x & a"\/"x = x by LATTICES:def 3; end; hence thesis by A1,LATTICES:def 17; end; theorem for L being lower-bounded Lattice holds Bottom L = Bottom LattPOSet L proof let L be lower-bounded Lattice; set x = %Bottom LattPOSet L; A1: %Bottom LattPOSet L = Bottom LattPOSet L by LATTICE3:def 4; now let a be Element of L; A2: x% = x by LATTICE3:def 3; a% >= Bottom LattPOSet L by YELLOW_0:44; then a% >= x% by A2,LATTICE3:def 4; then x [= a by LATTICE3:7; hence x"/\"a = x & a"/\"x = x by LATTICES:21; end; hence thesis by A1,LATTICES:def 16; end; begin :: Poset of Substitutions canceled; theorem for V being set, C being finite set, A, B being Element of Fin PFuncs (V, C) st A = {} & B <> {} holds B =>> A = {} proof let V be set, C be finite set, A, B be Element of Fin PFuncs (V, C); assume A1: A = {} & B <> {}; assume B =>> A <> {}; then consider k being set such that A2: k in B =>> A by XBOOLE_0:def 1; consider f being PartFunc of B, A such that A3: k = union {f.i \ i where i is Element of PFuncs (V, C) : i in B} & dom f = B by A2,HEYTING2:20; thus thesis by A1,A3,PARTFUN1:62; end; theorem Th12: for V, V', C, C' being set st V c= V' & C c= C' holds SubstitutionSet (V, C) c= SubstitutionSet (V', C') proof let V, V', C, C' be set; assume A1: V c= V' & C c= C'; let x be set; assume x in SubstitutionSet (V, C); then x in { A where A is Element of Fin PFuncs (V,C) : ( for u being set st u in A holds u is finite ) & for s, t being Element of PFuncs (V, C) holds ( s in A & t in A & s c= t implies s = t ) } by SUBSTLAT:def 1; then consider B being Element of Fin PFuncs (V,C) such that A2: B = x & ( for u being set st u in B holds u is finite ) & for s, t being Element of PFuncs (V, C) holds ( s in B & t in B & s c= t implies s = t ); A3: B in Fin PFuncs (V,C); A4: B c= PFuncs (V,C) by FINSUB_1:def 5; PFuncs (V,C) c= PFuncs (V',C') by A1,PARTFUN1:128; then Fin PFuncs (V,C) c= Fin PFuncs (V',C') by FINSUB_1:23; then reconsider B as Element of Fin PFuncs (V', C') by A3; for s, t being Element of PFuncs (V', C') st s in B & t in B & s c= t holds s = t by A2,A4; then x in { D where D is Element of Fin PFuncs (V', C') : ( for u being set st u in D holds u is finite ) & for s, t being Element of PFuncs (V', C') holds ( s in D & t in D & s c= t implies s = t ) } by A2; hence thesis by SUBSTLAT:def 1; end; theorem Th13: for V, V', C, C' being set, A being Element of Fin PFuncs (V, C), B being Element of Fin PFuncs (V', C') st V c= V' & C c= C' & A = B holds mi A = mi B proof let V, V', C, C' be set, A be Element of Fin PFuncs (V, C), B be Element of Fin PFuncs (V', C'); assume A1: V c= V' & C c= C' & A = B; hereby let x be set; assume A2: x in mi A; then x in { t where t is Element of PFuncs (V, C) : t is finite & for s being Element of PFuncs (V, C) holds ( s in A & s c= t iff s = t ) } by SUBSTLAT:def 2; then consider f being Element of PFuncs (V, C) such that A3: f = x & f is finite & for s being Element of PFuncs (V, C) holds ( s in A & s c= f iff s = f ); A4: x in PFuncs (V,C) by A3; PFuncs (V,C) c= PFuncs (V',C') by A1,PARTFUN1:128; then reconsider f as Element of PFuncs (V', C') by A3,A4; for s being Element of PFuncs (V', C') holds s in B & s c= f iff s = f by A1,A2,A3,SUBSTLAT:6; then x in { t where t is Element of PFuncs (V', C') : t is finite & for s being Element of PFuncs (V', C') holds ( s in B & s c= t iff s = t ) } by A3; hence x in mi B by SUBSTLAT:def 2; end; let x be set; assume A5: x in mi B; then x in { t where t is Element of PFuncs (V', C') : t is finite & for s being Element of PFuncs (V', C') holds ( s in B & s c= t iff s = t ) } by SUBSTLAT:def 2; then consider f being Element of PFuncs (V', C') such that A6: f = x & f is finite & for s being Element of PFuncs (V', C') holds ( s in B & s c= f iff s = f ); reconsider x' = x as finite set by A6; A7: mi B c= B by SUBSTLAT:8; for b being finite set st b in A & b c= x' holds b = x' by A1,A5,SUBSTLAT:6; hence x in mi A by A1,A5,A7,SUBSTLAT:7; end; theorem for V, V', C, C' being set st V c= V' & C c= C' holds the L_join of SubstLatt (V, C) = (the L_join of SubstLatt (V', C')) | [:the carrier of SubstLatt (V, C), the carrier of SubstLatt (V, C):] proof let V, V', C, C' be set; set K = SubstLatt (V, C), L = SubstLatt (V', C'); A1: SubstitutionSet (V, C) = the carrier of K by SUBSTLAT:def 4; A2: SubstitutionSet (V', C') = the carrier of L by SUBSTLAT:def 4; assume A3: V c= V' & C c= C'; then A4: SubstitutionSet (V, C) c= SubstitutionSet (V', C') by Th12; A5: the carrier of K c= the carrier of L by A1,A2,A3,Th12; reconsider B1 = the L_join of K as BinOp of the carrier of K; set B2 = (the L_join of L) | [:the carrier of K, the carrier of K:]; dom (the L_join of L) = [:the carrier of L, the carrier of L:] by FUNCT_2:def 1; then [:the carrier of K, the carrier of K:] c= dom (the L_join of L) by A5,ZFMISC_1:119; then A6: dom B2 = [:the carrier of K, the carrier of K:] by RELAT_1:91; rng B2 c= the carrier of K proof let x be set; assume x in rng B2; then consider y being set such that A7: y in dom B2 & x = B2.y by FUNCT_1:def 5; consider y1, y2 being set such that A8: y1 in the carrier of K & y2 in the carrier of K & y = [y1, y2] by A6,A7,ZFMISC_1:def 2; y1 in SubstitutionSet (V, C) & y2 in SubstitutionSet (V, C) by A8,SUBSTLAT:def 4; then reconsider y1' = y1, y2' = y2 as Element of SubstitutionSet (V', C') by A4; reconsider y11 = y1, y22 = y2 as Element of SubstitutionSet (V, C) by A8,SUBSTLAT:def 4; B2.y = (the L_join of L). [y1, y2] by A6,A7,A8,FUNCT_1:72 .= (the L_join of L). (y1, y2) by BINOP_1:def 1 .= mi (y1' \/ y2') by SUBSTLAT:def 4 .= mi (y11 \/ y22) by A3,Th13; hence thesis by A1,A7; end; then reconsider B2 as BinOp of the carrier of K by A6,FUNCT_2:4; now let a, b be Element of K; reconsider a' = a, b' = b as Element of SubstitutionSet (V, C) by SUBSTLAT:def 4; a' in SubstitutionSet (V, C) & b' in SubstitutionSet (V, C); then reconsider a1 = a, b1 = b as Element of SubstitutionSet (V', C') by A4; thus B1.(a, b) = mi (a' \/ b') by SUBSTLAT:def 4 .= mi (a1 \/ b1) by A3,Th13 .= (the L_join of L).(a, b) by SUBSTLAT:def 4 .= (the L_join of L).[a, b] by BINOP_1:def 1 .= B2.[a, b] by FUNCT_1:72 .= B2.(a, b) by BINOP_1:def 1; end; hence thesis by BINOP_1:2; end; definition let V, C be set; func SubstPoset (V, C) -> RelStr equals :Def1: LattPOSet SubstLatt (V, C); coherence; end; definition let V, C be set; cluster SubstPoset (V, C) -> with_suprema with_infima; coherence proof SubstPoset (V, C) = LattPOSet SubstLatt (V, C) by Def1; hence thesis; end; end; definition let V, C be set; cluster SubstPoset (V, C) -> reflexive antisymmetric transitive; coherence proof SubstPoset (V, C) = LattPOSet SubstLatt (V, C) by Def1; hence thesis; end; end; Lm5:now let V, C be set; A1: LattPOSet SubstLatt (V, C) = RelStr(#the carrier of SubstLatt (V, C), LattRel SubstLatt (V, C) #) by LATTICE3:def 2; SubstPoset (V, C) = LattPOSet SubstLatt (V, C) by Def1; hence SubstitutionSet (V, C) = the carrier of SubstPoset (V, C) by A1,SUBSTLAT:def 4; end; theorem Th15: for V, C being set, a, b being Element of SubstPoset (V, C) holds a <= b iff for x being set st x in a ex y being set st y in b & y c= x proof let V, C be set; let a, b be Element of SubstPoset (V, C); LattPOSet SubstLatt (V, C) = RelStr(#the carrier of SubstLatt (V, C), LattRel SubstLatt (V, C) #) by LATTICE3:def 2; then reconsider a' = a, b' = b as Element of SubstLatt (V, C) by Def1; reconsider a1 = a, b1 = b as Element of SubstitutionSet (V, C) by Lm5; A1: a'% = a & b'% = b by LATTICE3:def 3; A2: SubstPoset (V, C) = LattPOSet SubstLatt (V, C) by Def1; hereby assume a <= b; then a' [= b' by A1,A2,LATTICE3:7; then a' = a' "/\" b' by LATTICES:21 .= (the L_meet of SubstLatt (V, C)).(a',b') by LATTICES:def 2 .= mi (a1 ^ b1) by SUBSTLAT:def 4; hence for x being set st x in a ex y being set st y in b & y c= x by HEYTING2:8; end; assume for x being set st x in a ex y being set st y in b & y c= x; then mi (a1 ^ b1) = a1 by HEYTING2:9; then a' = (the L_meet of SubstLatt (V, C)).(a',b') by SUBSTLAT:def 4 .= a' "/\" b' by LATTICES:def 2; then a' [= b' by LATTICES:21; hence thesis by A1,A2,LATTICE3:7; end; theorem for V, V', C, C' being set st V c= V' & C c= C' holds SubstPoset (V, C) is full SubRelStr of SubstPoset (V', C') proof let V, V', C, C' be set; set K = SubstPoset (V, C), L = SubstPoset (V', C'); assume A1: V c= V' & C c= C'; A2: the carrier of K = SubstitutionSet (V, C) by Lm5; the carrier of L = SubstitutionSet (V', C') by Lm5; then A3: the carrier of K c= the carrier of L by A1,A2,Th12; now let a, b be set; assume A4: [a,b] in the InternalRel of K; then A5: a in the carrier of K & b in the carrier of K by ZFMISC_1:106; then reconsider a' = a, b' = b as Element of K; reconsider a1 = a, b1 = b as Element of L by A3,A5; a' <= b' by A4,ORDERS_1:def 9; then for x being set st x in a' ex y being set st y in b' & y c= x by Th15; then a1 <= b1 by Th15; hence [a,b] in the InternalRel of L by ORDERS_1:def 9; end; then the InternalRel of K c= the InternalRel of L by RELAT_1:def 3; then reconsider K as SubRelStr of L by A3,YELLOW_0:def 13; the InternalRel of K = (the InternalRel of L) |_2 the carrier of K proof now let x, y be set; assume A6: [x,y] in the InternalRel of K; then A7: x in the carrier of K & y in the carrier of K by ZFMISC_1:106; then reconsider p = x, q = y as Element of K; p <= q by A6,ORDERS_1:def 9; then A8: for a being set st a in p ex b being set st b in q & b c= a by Th15; reconsider p' = p, q' = q as Element of L by A3,A7; p' <= q' by A8,Th15; then [p',q'] in the InternalRel of L by ORDERS_1:def 9; hence [x,y] in (the InternalRel of L) |_2 the carrier of K by A6,WELLORD1:16; end; hence the InternalRel of K c= (the InternalRel of L) |_2 the carrier of K by RELAT_1:def 3; now let x, y be set; assume [x,y] in (the InternalRel of L) |_2 the carrier of K; then A9: [x,y] in (the InternalRel of L) & [x,y] in [:the carrier of K, the carrier of K:] by WELLORD1:16; then x in the carrier of L & y in the carrier of L by ZFMISC_1:106; then reconsider p = x, q = y as Element of L; p <= q by A9,ORDERS_1:def 9; then A10: for a being set st a in p ex b being set st b in q & b c= a by Th15; x in the carrier of K & y in the carrier of K by A9,ZFMISC_1:106; then reconsider p' = x, q' = y as Element of K; p' <= q' by A10,Th15; hence [x,y] in the InternalRel of K by ORDERS_1:def 9; end; hence (the InternalRel of L) |_2 the carrier of K c= the InternalRel of K by RELAT_1:def 3; end; hence thesis by YELLOW_0:def 14; end; definition let n, k be Nat; func PFArt (n, k) -> Element of PFuncs (NAT, {k}) means :Def2: for x being set holds x in it iff ( ex m being odd Nat st m <= 2*n & [m,k] = x ) or [2*n,k] = x; existence proof defpred P[set] means (( ex m being odd Nat st m <= 2*n & [m,k] = $1 ) or [2*n,k] = $1); consider X being set such that A1: for x being set holds x in X iff x in [:NAT,{k}:] & P[x] from Separation; A2: X c= [:NAT,{k}:] proof let x be set; assume x in X; hence thesis by A1; end; then reconsider X' = X as Function by GRFUNC_1:6; dom X' c= NAT & rng X' c= {k} by A2,SYSREL:15; then reconsider X as Element of PFuncs (NAT, {k}) by PARTFUN1:def 5; take X; let x be set; thus x in X implies ( ex m being odd Nat st m <= 2*n & [m,k] = x ) or [2*n,k] = x by A1; assume A3: ( ex m being odd Nat st m <= 2*n & [m,k] = x ) or [2*n,k] = x; per cases by A3; suppose ex m being odd Nat st m <= 2*n & [m,k] = x; then consider m being odd Nat such that A4: m <= 2*n & [m,k] = x; x in [:NAT,{k}:] by A4,ZFMISC_1:129; hence thesis by A1,A3; suppose A5: [2*n,k] = x; then x in [:NAT,{k}:] by ZFMISC_1:129; hence thesis by A1,A5; end; uniqueness proof defpred P[set] means ( ex m being odd Nat st m <= 2*n & [m,k] = $1 ) or [2*n,k] = $1; A6: for X1,X2 being Element of PFuncs (NAT, {k}) st (for x being set holds x in X1 iff P[x]) & (for x being set holds x in X2 iff P[x]) holds X1 = X2 from ElementEq; let X1,X2 be Element of PFuncs (NAT, {k}) such that A7: (for x being set holds x in X1 iff P[x]) & (for x being set holds x in X2 iff P[x]); thus thesis by A6,A7; end; end; definition let n, k be Nat; cluster PFArt (n, k) -> finite; coherence proof PFArt (n, k) c= [:Seg (2*n) \/ {0}, {k}:] proof let t be set; assume A1: t in PFArt (n, k); per cases by A1,Def2; suppose ex m1 being odd Nat st m1 <= 2*n & [m1,k] = t; then consider m1 being odd Nat such that A2: m1 <= 2*n & [m1,k] = t; 1 <= m1 by Th1; then m1 in Seg (2*n) by A2,FINSEQ_1:3; then m1 in Seg (2*n) \/ {0} by XBOOLE_0:def 2; hence thesis by A2,ZFMISC_1:129; suppose A3: [2*n,k] = t; now per cases; suppose n is non empty; then A4: 1 <= n by RLVECT_1:99; 2 > 1 & n >= 0 by NAT_1:18; then n <= 2*n by REAL_2:146; then 1 <= 2*n by A4,AXIOMS:22; then 2*n in Seg (2*n) by FINSEQ_1:3; then 2*n in Seg (2*n) \/ {0} by XBOOLE_0:def 2; hence thesis by A3,ZFMISC_1:129; suppose n is empty; then 2*n in {0} by TARSKI:def 1; then 2*n in Seg (2*n) \/ {0} by XBOOLE_0:def 2; hence thesis by A3,ZFMISC_1:129; end; hence thesis; end; hence thesis by FINSET_1:13; end; end; definition let n, k be Nat; func PFCrt (n, k) -> Element of PFuncs (NAT, {k}) means :Def3: for x being set holds x in it iff ( ex m being odd Nat st m <= 2*n + 1 & [m,k] = x ); existence proof defpred P[set] means ex m being odd Nat st m <= 2*n + 1 & [m,k] = $1; consider X being set such that A1: for x being set holds x in X iff x in [:NAT,{k}:] & P[x] from Separation; A2: X c= [:NAT,{k}:] proof let x be set; assume x in X; hence thesis by A1; end; then reconsider X' = X as Function by GRFUNC_1:6; dom X' c= NAT & rng X' c= {k} by A2,SYSREL:15; then reconsider X as Element of PFuncs (NAT, {k}) by PARTFUN1:def 5; take X; let x be set; thus x in X implies ex m being odd Nat st m <= 2*n + 1 & [m,k] = x by A1; given m being odd Nat such that A3: m <= 2*n + 1 & [m,k] = x; x in [:NAT,{k}:] by A3,ZFMISC_1:129; hence thesis by A1,A3; end; uniqueness proof defpred P[set] means ex m being odd Nat st m <= 2*n + 1 & [m,k] = $1; A4: for X1,X2 being Element of PFuncs (NAT, {k}) st (for x being set holds x in X1 iff P[x]) & (for x being set holds x in X2 iff P[x]) holds X1 = X2 from ElementEq; let X1,X2 being Element of PFuncs (NAT, {k}) such that A5: (for x being set holds x in X1 iff P[x]) & (for x being set holds x in X2 iff P[x]); thus thesis by A4,A5; end; end; definition let n,k be Nat; cluster PFCrt (n,k) -> finite; coherence proof set x = PFCrt (n,k); x c= [:Seg (2*n+1), {k}:] proof let t be set; assume t in x; then consider m being odd Nat such that A1: m <= 2*n + 1 & [m,k] = t by Def3; 1 <= m by Th1; then m in Seg (2*n+1) by A1,FINSEQ_1:3; hence thesis by A1,ZFMISC_1:129; end; hence thesis by FINSET_1:13; end; end; theorem Th17: for n, k being Nat holds [2*n+1,k] in PFCrt (n,k) proof let n, k be Nat; 2*n+1 is odd by SCMFSA9A:1; hence thesis by Def3; end; theorem Th18: for n, k being Nat holds PFCrt (n,k) misses {[2*n+3,k]} proof let n, k be Nat; assume PFCrt (n,k) /\ {[2*n+3,k]} <> {}; then consider x being set such that A1: x in PFCrt (n,k) /\ {[2*n+3,k]} by XBOOLE_0:def 1; A2: x in PFCrt (n,k) & x in {[2*n+3,k]} by A1,XBOOLE_0:def 3; then consider m being odd Nat such that A3: m <= 2*n + 1 & [m,k] = x by Def3; x = [2*n+3,k] by A2,TARSKI:def 1; then m = 2*n+3 by A3,ZFMISC_1:33; hence thesis by A3,REAL_1:53; end; Lm6:for n being Nat holds 2*n + 1 <= 2*(n+1) + 1 proof let n be Nat; 2*(n+1) + 1 = 2*n + 2*1 + 1 by XCMPLX_1:8 .= 2*n + 1 + 2 by XCMPLX_1:1; hence thesis by NAT_1:29; end; theorem Th19: for n, k being Nat holds PFCrt (n+1,k) = PFCrt (n,k) \/ {[2*n+3,k]} proof let n,k be Nat; A1: 2*(n+1)+1 = 2*n+2*1+1 by XCMPLX_1:8 .= 2*n+(2+1) by XCMPLX_1:1 .= 2*n+3; thus PFCrt (n+1,k) c= PFCrt (n,k) \/ {[2*n+3,k]} proof let x be set; assume x in PFCrt (n+1,k); then consider m being odd Nat such that A2: m <= 2*(n+1) + 1 & [m,k] = x by Def3; A3: 2*n+1+1 = 2*n+(1+1) by XCMPLX_1:1 .= 2*n+2*1 .= 2*(n+1) by XCMPLX_1:8; per cases by A2,NAT_1:27; suppose m <= 2*(n+1); then m <= 2*n + 2*1 by XCMPLX_1:8; then m <= 2*n + (1 + 1); then m <= 2*n + 1 + 1 by XCMPLX_1:1; then m <= 2*n + 1 or m = 2*n + 1 + 1 by NAT_1:26; then x in PFCrt (n,k) by A2,A3,Def3,ABIAN:def 2; hence thesis by XBOOLE_0:def 2; suppose m = 2*(n+1) + 1; then m = 2*n+2*1+1 by XCMPLX_1:8 .= 2*n+(2+1) by XCMPLX_1:1 .= 2*n+3; then x in {[2*n+3,k]} by A2,TARSKI:def 1; hence thesis by XBOOLE_0:def 2; end; let x be set; assume A4: x in PFCrt (n,k) \/ {[2*n+3,k]}; per cases by A4,XBOOLE_0:def 2; suppose x in PFCrt (n,k); then consider m being odd Nat such that A5: m <= 2*n + 1 & [m,k] = x by Def3; 2*n+1 <= 2*(n+1)+1 by Lm6; then m <= 2*(n+1) + 1 by A5,AXIOMS:22; hence thesis by A5,Def3; suppose x in {[2*n+3,k]}; then x = [2*n+3,k] by TARSKI:def 1; hence thesis by A1,Th17; end; Lm7: for n, n' being Nat holds not PFCrt (n+1,n') c= PFCrt (n,n') proof let n, n' be Nat; set k = [2*n+3,n']; PFCrt (n+1,n') = PFCrt (n,n') \/ {[2*n+3,n']} by Th19; then {k} c= PFCrt (n+1,n') by XBOOLE_1:7; then A1: k in PFCrt (n+1,n') by ZFMISC_1:37; PFCrt (n,n') misses {[2*n+3,n']} by Th18; then PFCrt (n,n') /\ {[2*n+3,n']} = {} by XBOOLE_0:def 7; hence thesis by A1,ZFMISC_1:52; end; theorem Th20: for n, k being Nat holds PFCrt (n,k) c< PFCrt (n+1,k) proof let n,k be Nat; thus PFCrt (n,k) c= PFCrt (n+1,k) proof let x be set; assume x in PFCrt (n,k); then consider m being odd Nat such that A1: m <= 2*n + 1 & [m,k] = x by Def3; 2*n + 1 <= 2*(n+1) + 1 by Lm6; then m <= 2*(n+1) + 1 by A1,AXIOMS:22; hence thesis by A1,Def3; end; thus PFCrt (n,k) <> PFCrt (n+1,k) by Lm7; end; definition let n, k be Nat; cluster PFArt (n, k) -> non empty; coherence proof [2*n, k] in PFArt (n, k) by Def2; hence thesis; end; end; theorem Th21: for n, m, k being Nat holds not PFArt (n, m) c= PFCrt (k, m) proof let n, m, k be Nat; set x = [2*n,m]; A1: x in PFArt (n, m) by Def2; not x in PFCrt (k,m) proof assume x in PFCrt (k,m); then consider m' being odd Nat such that A2: m' <= 2*k + 1 & [m',m] = x by Def3; m' = 2*n by A2,ZFMISC_1:33; hence thesis by ABIAN:def 2; end; hence thesis by A1; end; Lm8: for n, k being Nat holds PFCrt (n,k) c= PFCrt (n+1,k) proof let n, k be Nat; PFCrt (n,k) c< PFCrt (n+1,k) by Th20; hence thesis by XBOOLE_0:def 8; end; theorem for n, m, k being Nat st n <= k holds PFCrt (n,m) c= PFCrt (k,m) proof let n, m, k be Nat; assume n <= k; then 2*n <= 2*k by NAT_1:20; then A1: 2*n + 1 <= 2*k + 1 by AXIOMS:24; let x be set; assume x in PFCrt (n, m); then consider m' being odd Nat such that A2: m' <= 2*n + 1 & [m',m] = x by Def3; m' <= 2*k + 1 by A1,A2,AXIOMS:22; hence thesis by A2,Def3; end; Lm9: for n, m, k being Nat st n < k holds PFCrt (n,m) c= PFArt (k,m) proof let n, m, k be Nat; assume n < k; then 2*n < 2*k by REAL_1:70; then A1: 2*n + 1 <= 2*k by NAT_1:38; let x be set; assume x in PFCrt (n,m); then consider p being odd Nat such that A2: p <= 2*n + 1 & [p,m] = x by Def3; p <= 2*k by A1,A2,AXIOMS:22; hence thesis by A2,Def2; end; theorem for n being Nat holds PFArt (1,n) = { [1,n], [2,n] } proof let n be Nat; thus PFArt (1, n) c= { [1,n], [2,n] } proof let x be set; assume A1: x in PFArt (1, n); per cases by A1,Def2; suppose ex m being odd Nat st m <= 2*1 & [m,n] = x; then consider m being odd Nat such that A2: m <= 2*1 & [m,n] = x; x = [1,n] by A2,Lm3,CQC_THE1:3; hence thesis by TARSKI:def 2; suppose [2*1,n] = x; hence thesis by TARSKI:def 2; end; let x be set; assume A3: x in { [1,n], [2,n] }; per cases by A3,TARSKI:def 2; suppose A4: x = [1,n]; 1 <= 2 * 1; hence thesis by A4,Def2,Lm4; suppose x = [2,n]; then x = [2*1,n]; hence thesis by Def2; end; definition let n, k be Nat; func PFBrt (n,k) -> Element of Fin PFuncs (NAT, {k}) means :Def4: for x being set holds x in it iff ( ex m being non empty Nat st m <= n & x = PFArt (m,k) ) or x = PFCrt (n,k); existence proof defpred P[set] means ( ex m being non empty Nat st m <= n & $1 = PFArt (m,k) ) or $1 = PFCrt (n,k); consider X being set such that A1: for x being set holds x in X iff x in PFuncs (NAT, {k}) & P[x] from Separation; A2: X c= bool [:Seg (2*n+1), {k}:] proof let x be set; assume A3: x in X; per cases by A1,A3; suppose ex m being non empty Nat st m <= n & x = PFArt (m,k); then consider m being non empty Nat such that A4: m <= n & x = PFArt (m,k); A5: 2*m <= 2*n by A4,NAT_1:20; 2*n <= 2*n+1 by NAT_1:29; then A6: 2*m <= 2*n+1 by A5,AXIOMS:22; x c= [:Seg (2*n+1), {k}:] proof let t be set; assume A7: t in x; per cases by A4,A7,Def2; suppose ex m1 being odd Nat st m1 <= 2*m & [m1,k] = t; then consider m1 being odd Nat such that A8: m1 <= 2*m & [m1,k] = t; A9: 1 <= m1 by Th1; m1 <= 2*n+1 by A6,A8,AXIOMS:22; then m1 in Seg (2*n+1) by A9,FINSEQ_1:3; hence thesis by A8,ZFMISC_1:129; suppose A10: [2*m,k] = t; A11: 1 <= m by RLVECT_1:99; 2 > 1 & m >= 0 by NAT_1:18; then m <= 2*m by REAL_2:146; then 1 <= 2*m by A11,AXIOMS:22; then 2*m in Seg (2*n+1) by A6,FINSEQ_1:3; hence thesis by A10,ZFMISC_1:129; end; hence thesis; suppose A12: x = PFCrt (n,k); x c= [:Seg (2*n+1), {k}:] proof let t be set; assume t in x; then consider m being odd Nat such that A13: m <= 2*n + 1 & [m,k] = t by A12,Def3; 1 <= m by Th1; then m in Seg (2*n+1) by A13,FINSEQ_1:3; hence thesis by A13,ZFMISC_1:129; end; hence thesis; end; bool [:Seg (2*n+1), {k}:] is finite by FINSET_1:24; then A14: X is finite by A2,FINSET_1:13; X c= PFuncs (NAT, {k}) proof let x be set; assume x in X; hence thesis by A1; end; then reconsider X as Element of Fin PFuncs (NAT, {k}) by A14,FINSUB_1:def 5 ; take X; let x be set; thus x in X implies ( ex m being non empty Nat st m <= n & x = PFArt (m,k) ) or x = PFCrt (n,k) by A1; assume ( ex m being non empty Nat st m <= n & x = PFArt (m,k) ) or x = PFCrt (n,k); hence thesis by A1; end; uniqueness proof defpred P[set] means ( ex m being non empty Nat st m <= n & $1 = PFArt (m,k) ) or $1 = PFCrt (n,k); A15: for X1,X2 being Element of Fin PFuncs (NAT, {k}) st (for x being set holds x in X1 iff P[x]) & (for x being set holds x in X2 iff P[x]) holds X1 = X2 from ElementEq; let X1,X2 being Element of Fin PFuncs (NAT, {k}) such that A16: (for x being set holds x in X1 iff P[x]) & (for x being set holds x in X2 iff P[x]); thus thesis by A15,A16; end; end; theorem for n, k being Nat, x being set st x in PFBrt (n+1,k) holds ex y being set st y in PFBrt (n,k) & y c= x proof let n, k be Nat, x be set; assume A1: x in PFBrt (n+1,k); per cases by A1,Def4; suppose ex m being non empty Nat st m <= n+1 & x = PFArt (m,k); then consider m being non empty Nat such that A2: m <= n+1 & x = PFArt (m,k); thus ex y being set st y in PFBrt (n,k) & y c= x proof per cases by A2,NAT_1:26; suppose A3: m <= n; take y = x; thus y in PFBrt (n,k) by A2,A3,Def4; thus y c= x; suppose A4: m = n+1; take y = PFCrt (n,k); n < n+1 by NAT_1:38; hence y in PFBrt (n,k) & y c= x by A2,A4,Def4,Lm9; end; suppose A5: x = PFCrt (n+1,k); take y = PFCrt (n,k); thus y in PFBrt (n,k) by Def4; thus y c= x by A5,Lm8; end; theorem for n, k being Nat holds not PFCrt (n,k) in PFBrt (n+1,k) proof let n, k be Nat; assume PFCrt (n,k) in PFBrt (n+1,k); then ( ex m being non empty Nat st m <= n+1 & PFCrt (n,k) = PFArt (m,k) ) or PFCrt (n,k) = PFCrt (n+1,k) by Def4; then consider m being Nat such that A1: m <= n+1 & PFCrt (n,k) = PFArt (m,k) by Th20; thus thesis by A1,Th21; end; Lm10: for n, k being Nat, x being set st x in PFBrt (n,k) holds x is finite proof let n,k be Nat, x be set; assume x in PFBrt (n,k); then A1: ( ex m being non empty Nat st m <= n & x = PFArt (m,k) ) or x = PFCrt (n,k) by Def4; per cases by A1; suppose ex m being Nat st m <= n & x = PFArt (m,k); then consider m being Nat such that A2: m <= n & x = PFArt (m,k); thus thesis by A2; suppose x = PFCrt (n,k); hence thesis; end; theorem Th26: for n, m, k being Nat st PFArt (n,m) c= PFArt (k,m) holds n = k proof let n, m, k be Nat; assume A1: PFArt (n,m) c= PFArt (k,m); assume n <> k; then A2: 2*n <> 2*k by XCMPLX_1:5; A3: [2*n,m] in PFArt (n,m) by Def2; [2*n,m] <> [2*k,m] by A2,ZFMISC_1:33; then consider m' being odd Nat such that A4: m' <= 2*k & [m',m] = [2*n,m] by A1,A3,Def2; m'= 2*n by A4,ZFMISC_1:33; hence thesis by ABIAN:def 2; end; theorem Th27: for n, m, k being Nat holds PFCrt (n,m) c= PFArt (k,m) iff n < k proof let n, m, k be Nat; thus PFCrt (n,m) c= PFArt (k,m) implies n < k proof assume A1: PFCrt (n,m) c= PFArt (k,m); assume A2: k <= n; A3: [2*n+1,m] in PFCrt (n,m) by Th17; not [2*n+1,m] in PFArt (k,m) proof assume A4: [2*n+1,m] in PFArt (k,m); per cases by A4,Def2; suppose ex m' being odd Nat st m' <= 2*k & [m',m] = [2*n+1,m]; then consider m' being odd Nat such that A5: m' <= 2*k & [m',m] = [2*n+1,m]; A6: 2*n+1 <= 2*k by A5,ZFMISC_1:33; 2*k <= 2*n by A2,NAT_1:20; hence thesis by A6,NAT_1:38; suppose [2*k,m] = [2*n+1,m]; then A7: 2*k = 2*n+1 by ZFMISC_1:33; 2*k is even by ABIAN:def 2; hence thesis by A7,SCMFSA9A:1; end; hence thesis by A1,A3; end; thus thesis by Lm9; end; begin :: Uncompleteness theorem Th28: for n, k being Nat holds PFBrt (n,k) is Element of SubstPoset (NAT, {k}) proof let n, k be Nat; A1: for u being set st u in PFBrt (n,k) holds u is finite by Lm10; A2:SubstitutionSet (NAT, {k}) = the carrier of SubstPoset (NAT, {k}) by Lm5; for s, t being Element of PFuncs (NAT,{k}) holds ( s in PFBrt (n,k) & t in PFBrt (n,k) & s c= t implies s = t ) proof let s, t be Element of PFuncs (NAT,{k}); assume A3: s in PFBrt (n,k) & t in PFBrt (n,k) & s c= t; then A4: ( ex m being non empty Nat st m <= n & s = PFArt (m,k) ) or s = PFCrt (n,k) by Def4; A5: ( ex m being non empty Nat st m <= n & t = PFArt (m,k) ) or t = PFCrt (n,k) by A3,Def4; per cases by A4,A5; suppose A6: ( ex m being Nat st m <= n & s = PFArt (m,k) ) & ( ex m being Nat st m <= n & t = PFArt (m,k) ); then consider m1 being Nat such that A7: m1 <= n & s = PFArt (m1,k); consider m2 being Nat such that A8: m2 <= n & t = PFArt (m2,k) by A6; thus thesis by A3,A7,A8,Th26; suppose ( ex m being Nat st m <= n & s = PFArt (m,k) ) & t = PFCrt (n,k) ; hence thesis by A3,Th21; suppose s = PFCrt (n,k) & ex m being Nat st m <= n & t = PFArt (m,k); hence thesis by A3,Th27; suppose s = PFCrt (n,k) & t = PFCrt (n,k); hence thesis; end; then PFBrt (n,k) in { A where A is Element of Fin PFuncs (NAT,{k}) : ( for u being set st u in A holds u is finite ) & for s, t being Element of PFuncs (NAT,{k}) holds ( s in A & t in A & s c= t implies s = t ) } by A1; then PFBrt (n,k) in SubstitutionSet (NAT, {k}) by SUBSTLAT:def 1; hence thesis by A2; end; definition let k be Nat; func PFDrt k -> Subset of SubstPoset (NAT, {k}) means :Def5: for x being set holds x in it iff ex n being non empty Nat st x = PFBrt (n,k); existence proof defpred P[set] means ex n being non empty Nat st $1 = PFBrt (n,k); consider X being set such that A1: for x being set holds x in X iff x in the carrier of SubstPoset (NAT, {k}) & P[x] from Separation; X c= the carrier of SubstPoset (NAT, {k}) proof let x be set; assume x in X; hence thesis by A1; end; then reconsider X' = X as Subset of SubstPoset (NAT, {k}) ; take X'; let x be set; thus x in X' implies ex n being non empty Nat st x = PFBrt (n,k) by A1; given n being non empty Nat such that A2: x = PFBrt (n, k); x is Element of SubstPoset (NAT, {k}) by A2,Th28; hence thesis by A1,A2; end; uniqueness proof defpred P[set] means ex n being non empty Nat st $1 = PFBrt (n,k); A3: for A1, A2 being Subset of SubstPoset (NAT, {k}) st (for x being set holds x in A1 iff P[x]) & (for x being set holds x in A2 iff P[x]) holds A1 = A2 from SSubsetUniq; let A1, A2 being Subset of SubstPoset (NAT, {k}) such that A4: (for x being set holds x in A1 iff P[x]) & (for x being set holds x in A2 iff P[x]); thus thesis by A3,A4; end; end; theorem for k being Nat holds PFBrt (1,k) = { PFArt (1,k), PFCrt (1,k) } proof let k be Nat; thus PFBrt (1,k) c= { PFArt (1,k), PFCrt (1,k) } proof let x be set; assume A1: x in PFBrt (1,k); per cases by A1,Def4; suppose ex m being non empty Nat st m <= 1 & x = PFArt (m,k); then consider m being non empty Nat such that A2: m <= 1 & x = PFArt (m,k); m >= 1 by RLVECT_1:99; then m = 1 by A2,AXIOMS:21; hence thesis by A2,TARSKI:def 2; suppose x = PFCrt (1,k); hence thesis by TARSKI:def 2; end; let x be set; assume A3: x in { PFArt (1,k), PFCrt (1,k) }; per cases by A3,TARSKI:def 2; suppose x = PFArt (1,k); hence thesis by Def4; suppose x = PFCrt (1,k); hence thesis by Def4; end; theorem Th30: for k being Nat holds PFBrt (1,k) <> {{}} proof let k be Nat; PFArt (1,k) in PFBrt (1,k) by Def4; hence thesis by TARSKI:def 1; end; definition let k be Nat; cluster PFBrt (1,k) -> non empty; coherence proof PFArt (1,k) in PFBrt (1,k) by Def4; hence thesis; end; end; theorem Th31: for n, k being Nat holds { PFArt (n,k) } is Element of SubstPoset (NAT, {k}) proof let n, k be Nat; A1: LattPOSet SubstLatt (NAT, {k}) = RelStr(#the carrier of SubstLatt (NAT, {k}), LattRel SubstLatt (NAT, {k})#) by LATTICE3:def 2; SubstitutionSet (NAT, {k}) = the carrier of SubstLatt (NAT, {k}) by SUBSTLAT:def 4 .= the carrier of SubstPoset (NAT, {k}) by A1,Def1; then { PFArt (n,k) } is Element of SubstPoset (NAT, {k}) by HEYTING2:6; hence thesis; end; theorem Th32: for k being Nat, V, X being set, a being Element of SubstPoset (V, {k}) st X in a holds X is finite Subset of [:V, {k}:] proof let k be Nat; let V, X be set; let a be Element of SubstPoset (V, {k}); A1: LattPOSet SubstLatt (V, {k}) = RelStr(#the carrier of SubstLatt (V, {k}), LattRel SubstLatt (V, {k})#) by LATTICE3:def 2; A2: SubstitutionSet (V, {k}) = the carrier of SubstLatt (V, {k}) by SUBSTLAT:def 4 .= the carrier of SubstPoset (V, {k}) by A1,Def1; then a in SubstitutionSet (V, {k}); then A3: a c= PFuncs (V, {k}) & a is finite by FINSUB_1:def 5; assume A4: X in a; then A5: X in PFuncs (V, {k}) by A3; PFuncs (V, {k}) c= bool [:V, {k}:] by HEYTING2:4; hence thesis by A2,A4,A5,HEYTING2:2; end; theorem Th33: for m being Nat, a being Element of SubstPoset (NAT, {m}) st PFDrt m is_>=_than a holds for X being non empty set st X in a holds not ( for n being Nat st [n,m] in X holds n is odd ) proof let m be Nat; let a be Element of SubstPoset (NAT, {m}); assume A1: PFDrt m is_>=_than a; let X be non empty set; assume A2: X in a; then reconsider X'= X as finite non empty Subset of [:NAT,{m}:] by Th32; assume A3: for n being Nat st [n,m] in X holds n is odd; A4: now let k be non empty Nat; reconsider Pk = PFBrt (k,m) as Element of SubstPoset (NAT, {m}) by Th28; Pk in PFDrt m by Def5; then a <= Pk by A1,LATTICE3:def 8; then consider y being set such that A5: y in Pk & y c= X by A2,Th15; A6: ( ex m' being non empty Nat st m' <= k & y = PFArt (m',m) ) or y = PFCrt (k,m) by A5,Def4; A7: not ex m' being Nat st m' <= k & y = PFArt (m',m) proof given m' being Nat such that A8: m' <= k & y = PFArt (m',m); [2*m',m] in PFArt (m',m) by Def2; then 2*m' is odd by A3,A5,A8; hence thesis by ABIAN:def 2; end; [2*k+1,m] in PFCrt (k,m) by Th17; hence [2*k+1,m] in X by A5,A6,A7; end; consider l being non empty Nat such that A9: not [2*l+1,m] in X' by Th6; thus thesis by A4,A9; end; theorem Th34: for k being Nat, a, b being Element of SubstPoset (NAT, {k}), X being Subset of SubstPoset (NAT, {k}) st a is_<=_than X & b is_<=_than X holds a "\/" b is_<=_than X proof let k be Nat; let a, b be Element of SubstPoset (NAT, {k}), X be Subset of SubstPoset (NAT, {k}); assume A1: a is_<=_than X & b is_<=_than X; let c be Element of SubstPoset (NAT, {k}); assume c in X; then a <= c & b <= c by A1,LATTICE3:def 8; hence thesis by YELLOW_5:9; end; definition let k be Nat; cluster non empty Element of SubstPoset (NAT, {k}); existence proof SubstitutionSet (NAT, {k}) = the carrier of SubstPoset (NAT, {k}) by Lm5; then {{}} in the carrier of SubstPoset (NAT, {k}) by SUBSTLAT:2; then reconsider E = {{}} as Element of SubstPoset (NAT, {k}) ; take E; thus thesis; end; end; Lm11: for a being non empty set st a <> {{}} & {} in a ex b being set st b in a & b <> {} proof let a be non empty set; assume A1: a <> {{}} & {} in a; assume A2: for b being set st b in a holds b = {}; a = {{}} proof thus a c= {{}} proof let x be set; assume x in a; then x = {} by A2; hence thesis by TARSKI:def 1; end; let x be set; assume x in {{}}; hence thesis by A1,TARSKI:def 1; end; hence thesis by A1; end; theorem Th35: for n being Nat, a being Element of SubstPoset (NAT, {n}) st {} in a holds a = {{}} proof let n be Nat; let a be Element of SubstPoset (NAT, {n}); SubstitutionSet (NAT, {n}) = the carrier of SubstPoset (NAT, {n}) by Lm5; then A1: a in SubstitutionSet (NAT, {n}); assume A2: {} in a; assume a <> {{}}; then consider k being set such that A3: k in a & k <> {} by A2,Lm11; A4: a c= PFuncs (NAT, {n}) by A1,FINSUB_1:def 5; {} is PartFunc of NAT, {n} by PARTFUN1:56; then reconsider E = {}, K = k as Element of PFuncs (NAT, {n}) by A3,A4,PARTFUN1:119; E in a & K in a & E c= K by A2,A3,XBOOLE_1:2; hence thesis by A1,A3,SUBSTLAT:5; end; theorem Th36: for k being Nat, a being non empty Element of SubstPoset (NAT, {k}) st a <> {{}} ex f being finite Function st f in a & f <> {} proof let k be Nat; let a be non empty Element of SubstPoset (NAT, {k}); assume A1: a <> {{}}; consider f being set such that A2: f in a by XBOOLE_0:def 1; SubstitutionSet (NAT, {k}) = the carrier of SubstPoset (NAT, {k}) by Lm5; then reconsider f as finite Function by A2,HEYTING2:2; take f; thus f in a by A2; assume f = {}; hence thesis by A1,A2,Th35; end; theorem Th37: for k being Nat, a being non empty Element of SubstPoset (NAT, {k}), a' being Element of Fin PFuncs (NAT, {k}) st a <> {{}} & a = a' holds Involved a' is finite non empty Subset of NAT proof let k be Nat; let a be non empty Element of SubstPoset (NAT, {k}); let a' be Element of Fin PFuncs (NAT, {k}); assume that A1: a <> {{}} and A2: a = a'; consider f being finite Function such that A3: f in a & f <> {} by A1,Th36; dom f <> {} by A3,RELAT_1:64; then consider k1 being set such that A4: k1 in dom f by XBOOLE_0:def 1; thus thesis by A2,A3,A4,HEYTING2:10,12,def 1; end; theorem Th38: for k being Nat, a being Element of SubstPoset (NAT, {k}), a' being Element of Fin PFuncs (NAT, {k}), B being finite non empty Subset of NAT st B = Involved a' & a' = a holds for X being set st X in a for l being Nat st l > max B + 1 holds not [l,k] in X proof let k be Nat, a be Element of SubstPoset (NAT, {k}), a' be Element of Fin PFuncs (NAT, {k}), B be finite non empty Subset of NAT; assume A1: B = Involved a' & a' = a; let X be set; assume A2: X in a; let l be Nat; assume A3: l > max B + 1; assume A4: [l,k] in X; SubstitutionSet (NAT, {k}) = the carrier of SubstPoset (NAT, {k}) by Lm5; then reconsider X' = X as finite Function by A2,HEYTING2:2; A5: max B + 1 >= max B by NAT_1:29; l in dom X' by A4,RELAT_1:def 4; then l in Involved a' by A1,A2,HEYTING2:def 1; then max B >= l by A1,FRECHET2:51; hence thesis by A3,A5,AXIOMS:22; end; theorem Th39: for k being Nat holds Top SubstPoset (NAT, {k}) = {{}} proof let k be Nat; A1: SubstitutionSet (NAT, {k}) = the carrier of SubstPoset (NAT, {k}) by Lm5; {{}} in SubstitutionSet (NAT, {k}) by SUBSTLAT:2; then reconsider a = {{}} as Element of SubstPoset (NAT, {k}) by A1; A2: a is_<=_than {} by YELLOW_0:6; for b being Element of SubstPoset (NAT, {k}) st b is_<=_than {} holds a >= b proof let b be Element of SubstPoset (NAT, {k}); assume b is_<=_than {}; now let x be set; assume x in b; take y = {}; thus y in a & y c= x by TARSKI:def 1,XBOOLE_1:2; end; hence thesis by Th15; end; then a = "/\"({},SubstPoset (NAT, {k})) by A2,YELLOW_0:31; hence thesis by YELLOW_0:def 12; end; theorem Th40: for k being Nat holds Bottom SubstPoset (NAT, {k}) = {} proof let k be Nat; A1:SubstitutionSet (NAT, {k}) = the carrier of SubstPoset (NAT, {k}) by Lm5; {} in SubstitutionSet (NAT, {k}) by SUBSTLAT:1; then reconsider a = {} as Element of SubstPoset (NAT, {k}) by A1; A2: a is_>=_than {} by YELLOW_0:6; for b being Element of SubstPoset (NAT, {k}) st b is_>=_than {} holds a <= b proof let b be Element of SubstPoset (NAT, {k}); assume b is_>=_than {}; for x be set st x in a ex y being set st y in b & y c= x; hence thesis by Th15; end; then a = "\/"({},SubstPoset (NAT, {k})) by A2,YELLOW_0:30; hence thesis by YELLOW_0:def 11; end; theorem Th41: for k being Nat, a, b being Element of SubstPoset (NAT, {k}) st a <= b & a = {{}} holds b = {{}} proof let k be Nat, a, b be Element of SubstPoset (NAT, {k}); A1:SubstPoset (NAT, {k}) = LattPOSet SubstLatt (NAT, {k}) by Def1; A2:Top SubstPoset (NAT, {k}) = {{}} by Th39; assume a <= b & a = {{}}; hence thesis by A1,A2,WAYBEL15:5; end; theorem Th42: for k being Nat, a, b being Element of SubstPoset (NAT, {k}) st a <= b & b = {} holds a = {} proof let k be Nat, a, b be Element of SubstPoset (NAT, {k}); A1:SubstPoset (NAT, {k}) = LattPOSet SubstLatt (NAT, {k}) by Def1; A2:Bottom SubstPoset (NAT, {k}) = {} by Th40; assume a <= b & b = {}; hence thesis by A1,A2,YELLOW_5:22; end; theorem Th43: for m being Nat, a being Element of SubstPoset (NAT, {m}) st PFDrt m is_>=_than a holds a <> {{}} proof let m be Nat; let a be Element of SubstPoset (NAT, {m}); assume A1: PFDrt m is_>=_than a; assume A2: a = {{}}; A3: PFBrt (1,m) in PFDrt m by Def5; reconsider P1 = PFBrt (1,m) as Element of SubstPoset (NAT, {m}) by Th28; A4: SubstPoset (NAT, {m}) = LattPOSet SubstLatt (NAT, {m}) by Def1; A5: Top SubstPoset (NAT, {m}) = {{}} by Th39; P1 >= a by A1,A3,LATTICE3:def 8; then P1 = {{}} by A2,A4,A5,WAYBEL15:5; hence thesis by Th30; end; Lm12: for m being Nat holds SubstPoset (NAT, {m}) is not complete proof let m be Nat; A1: SubstitutionSet (NAT, {m}) = the carrier of SubstPoset (NAT, {m}) by Lm5; assume SubstPoset (NAT, {m}) is complete; then consider a being Element of SubstPoset (NAT, {m}) such that A2: PFDrt m is_>=_than a & for b being Element of SubstPoset (NAT, {m}) st PFDrt m is_>=_than b holds a >= b by LATTICE5:def 2; {} in SubstitutionSet (NAT, {m}) by SUBSTLAT:1; then reconsider EM = {} as Element of SubstPoset (NAT, {m}) by A1; A3: a <> {{}} by A2,Th43; a in SubstitutionSet (NAT, {m}) by A1; then reconsider a' = a as Element of Fin PFuncs (NAT, {m}); set Mi = Involved a'; reconsider Cos = { PFArt (1,m) } as Element of SubstPoset (NAT, {m}) by Th31; A4: PFDrt m is_>=_than Cos proof let u be Element of SubstPoset (NAT, {m}); assume u in PFDrt m; then consider n1 being non empty Nat such that A5: u = PFBrt (n1,m) by Def5; now let d be set; assume d in Cos; then A6: d = PFArt (1,m) by TARSKI:def 1; 1 <= n1 by RLVECT_1:99; then d in PFBrt (n1,m) by A6,Def4; hence ex e be set st e in u & e c= d by A5; end; hence thesis by Th15; end; a <> {} proof assume a = {}; then EM >= Cos by A2,A4; hence thesis by Th42; end; then reconsider Mi as finite non empty Subset of NAT by A3,Th37; reconsider mX = max Mi + 1 as non empty Nat by ORDINAL2:def 21; mX >= 1 by RLVECT_1:99; then A7: mX > 0 by AXIOMS:22; reconsider Sum = { PFArt (mX,m) } as Element of SubstPoset (NAT, {m}) by Th31; set b = a "\/" Sum; Sum is_<=_than PFDrt m proof let t be Element of SubstPoset (NAT, {m}); assume t in PFDrt m; then consider n being non empty Nat such that A8: t = PFBrt (n,m) by Def5; for x being set st x in Sum ex y being set st y in t & y c= x proof let x be set; assume A9: x in Sum; then A10: x = PFArt (mX,m) by TARSKI:def 1; per cases; suppose A11: n < mX; take y = PFCrt (n,m); thus y in t by A8,Def4; thus y c= x by A10,A11,Lm9; suppose A12: n >= mX; take y = PFArt (mX,m); thus y in t by A8,A12,Def4; thus y c= x by A9,TARSKI:def 1; end; hence Sum <= t by Th15; end; then A13: PFDrt m is_>=_than b by A2,Th34; A14: a <= b by YELLOW_0:22; a <> b proof assume A15: a = b; then A16: Sum <= a by YELLOW_0:24; PFArt (mX,m) in Sum by TARSKI:def 1; then consider g being set such that A17: g in a & g c= PFArt (mX,m) by A16,Th15; per cases; suppose g is non empty; then consider n being Nat such that A18: [n,m] in g & n is even by A2,A17,Th33; now per cases by A17,A18,Def2; suppose ex m' being odd Nat st m' <= 2*mX & [m',m] = [n,m]; then consider m' being odd Nat such that A19: m' <= 2*mX & [m',m] = [n,m]; thus thesis by A18,A19,ZFMISC_1:33; suppose A20: [2*mX,m] = [n,m]; 2*mX > mX by A7,REAL_2:144; hence thesis by A17,A18,A20,Th38; end; hence thesis; suppose g is empty; then A21: b = {{}} by A15,A17,Th35; reconsider P1 = PFBrt (1,m) as Element of SubstPoset (NAT, {m}) by Th28; A22: PFBrt (1,m) <> {{}} by Th30; PFBrt (1,m) in PFDrt m by Def5; then P1 >= b by A13,LATTICE3:def 8; hence thesis by A21,A22,Th41; end; then A23: a < b by A14,ORDERS_1:def 10; a >= b by A2,A13; hence contradiction by A23,ORDERS_1:30; end; definition let m be Nat; cluster SubstPoset (NAT, {m}) -> non complete; coherence by Lm12; end; definition let m be Nat; cluster SubstLatt (NAT, {m}) -> non complete; coherence proof assume SubstLatt (NAT, {m}) is complete; then reconsider K = SubstLatt (NAT, {m}) as complete Lattice; A1: LattPOSet K is complete; SubstPoset (NAT, {m}) is non complete; hence thesis by A1,Def1; end; end;