Copyright (c) 1991 Association of Mizar Users
environ vocabulary TREES_2, FINSEQ_1, BOOLE, TREES_1, FUNCT_1, RELAT_1, ZFMISC_1, PARTFUN1, ORDINAL1, TARSKI, FINSET_1, PRELAMB, CARD_1, FUNCOP_1, QC_LANG1, MCART_1, ZF_LANG, SEQ_1, MODAL_1; notation TARSKI, XBOOLE_0, ENUMSET1, ZFMISC_1, SUBSET_1, NUMBERS, XREAL_0, NAT_1, DOMAIN_1, MCART_1, RELAT_1, FUNCT_1, RELSET_1, FINSEQ_1, FINSEQ_2, FUNCT_2, FINSET_1, CARD_1, PARTFUN1, TREES_1, TREES_2, PRELAMB; constructors WELLORD2, NAT_1, DOMAIN_1, PARTFUN1, PRELAMB, XREAL_0, MEMBERED, XBOOLE_0; clusters SUBSET_1, FINSEQ_1, TREES_1, TREES_2, PRELAMB, FINSET_1, RELSET_1, XREAL_0, ARYTM_3, MEMBERED, ZFMISC_1, XBOOLE_0, ORDINAL2, NUMBERS; requirements NUMERALS, REAL, BOOLE, SUBSET, ARITHM; definitions TARSKI, XBOOLE_0; theorems TARSKI, FUNCT_1, REAL_1, NAT_1, ENUMSET1, TREES_1, TREES_2, FUNCOP_1, PRELAMB, MCART_1, DOMAIN_1, PARTFUN1, FINSEQ_1, FINSET_1, CARD_1, AXIOMS, WELLORD2, CARD_2, ZFMISC_1, CQC_THE1, FINSEQ_2, RELAT_1, FUNCT_2, RELSET_1, GROUP_3, XBOOLE_0, XBOOLE_1; schemes TREES_2, FUNCT_1, FINSEQ_2, NAT_1, FUNCT_2, XBOOLE_0; begin reserve x,y,x1,x2,y1,y2,z for set, n,m,k for Nat, t1 for DecoratedTree of [: NAT,NAT :], w,s,t,u for FinSequence of NAT, D for non empty set; Lm1: {} is_a_proper_prefix_of <*m*> proof A1: {} is_a_prefix_of <*m*> by XBOOLE_1:2; {} <> <*m*> by TREES_1:4; hence thesis by A1,XBOOLE_0:def 8; end; definition let Z be Tree; func Root Z -> Element of Z equals :Def1: {}; coherence by TREES_1:47; end; definition let D; let T be DecoratedTree of D; func Root T -> Element of D equals :Def2: T.(Root dom T); coherence; end; canceled 2; theorem Th3: n <> m implies not <*n*>,<*m*>^s are_c=-comparable proof assume A1: n<>m; assume A2: <*n*>,<*m*>^s are_c=-comparable; per cases by A2,XBOOLE_0:def 9; suppose <*n*> is_a_prefix_of <*m*>^s; then A3: ex a be FinSequence st <*m*>^s = <*n*>^a by TREES_1:8; m = (<*m*>^s).1 by FINSEQ_1:58 .= n by A3,FINSEQ_1:58; hence contradiction by A1; suppose <*m*>^s is_a_prefix_of <*n*>; then consider a be FinSequence such that A4: <*n*> = <*m*>^s^a by TREES_1:8; n = (<*m*>^s^a).1 by A4,FINSEQ_1:57 .= (<*m*>^(s^a)).1 by FINSEQ_1:45 .= m by FINSEQ_1:58; hence contradiction by A1; end; theorem Th4: for s st s <> {} ex w,n st s = <*n*>^w proof defpred P[FinSequence of NAT] means $1 <> {} implies ex w,n st $1 = <*n*>^w; A1: P[<*> NAT]; A2: for s,m st P[s] holds P[s^<*m*>] proof let s,m such that A3: s <> {} implies ex w,n st s = <*n*>^w; assume s^<*m*> <> {}; per cases; suppose A4: s = {}; reconsider w = <*> NAT as FinSequence of NAT; take w, n = m; thus s^<*m*> = <*m*> by A4,FINSEQ_1:47 .= <*n*>^w by FINSEQ_1:47; suppose s <> {}; then consider w,n such that A5: s = <*n*>^w by A3; take w1 = w^<*m*>,n; thus s^<*m*> =<*n*>^w1 by A5,FINSEQ_1:45; end; for p being FinSequence of NAT holds P[p] from IndSeqD(A1,A2); hence thesis; end; theorem Th5: n <> m implies not <*n*> is_a_proper_prefix_of <*m*>^s proof assume A1: n <> m; assume <*n*> is_a_proper_prefix_of <*m*>^s; then <*n*> is_a_prefix_of <*m*>^s by XBOOLE_0:def 8; then A2: ex a be FinSequence st <*m*>^s = <*n*>^a by TREES_1:8; m = (<*m*>^s).1 by FINSEQ_1:58 .= n by A2,FINSEQ_1:58; hence contradiction by A1; end; theorem Th6: n <> m implies not <*n*> is_a_prefix_of <*m*>^s proof assume A1: n <> m; assume <*n*> is_a_prefix_of <*m*>^s; then A2: ex a be FinSequence st <*m*>^s = <*n*>^a by TREES_1:8; m = (<*m*>^s).1 by FINSEQ_1:58 .= n by A2,FINSEQ_1:58; hence contradiction by A1; end; theorem Th7: not <*n*> is_a_proper_prefix_of <*m*> proof assume not thesis; then <*n*> is_a_prefix_of <*m*> & <*n*> <> <*m*> by XBOOLE_0:def 8; hence contradiction by TREES_1:16; end; canceled; theorem Th9: elementary_tree 1 = {{},<*0*>} proof A1: elementary_tree 1 = { <*n*> : n < 1 } \/ {{}} by TREES_1:def 7; now let x; thus x in {{},<*0*>} implies x in { <*n*> : n < 1 } or x in {{}} proof assume x in {{},<*0*>}; then x = {} or x = <*0*> by TARSKI:def 2; hence thesis by TARSKI:def 1; end; assume A2: x in { <*n*> : n < 1 } or x in {{}}; now per cases by A2; suppose x in { <*n*> : n < 1 }; then consider n such that A3: x = <*n*> & n < 1; n = 0 by A3,CQC_THE1:2; hence x in {{},<*0*>} by A3,TARSKI:def 2; suppose x in {{}}; then x = {} by TARSKI:def 1; hence x in {{},<*0*>} by TARSKI:def 2; end; hence x in {{},<*0*>}; end; hence thesis by A1,XBOOLE_0:def 2; end; theorem Th10: elementary_tree 2 = {{},<*0*>,<*1*>} proof A1: elementary_tree 2 = { <*n*> : n < 2 } \/ {{}} by TREES_1:def 7; now let x; thus x in {{},<*0*>,<*1*>} implies x in { <*n*> : n < 2 } or x in {{}} proof assume x in {{},<*0*>,<*1*>}; then x = {} or x = <*0*> or x = <*1*> by ENUMSET1:13; hence thesis by TARSKI:def 1; end; assume A2: x in { <*n*> : n < 2 } or x in {{}}; now per cases by A2; suppose x in { <*n*> : n < 2 }; then consider n such that A3: x = <*n*> & n < 2; n = 0 or n = 1 by A3,CQC_THE1:3; hence x in {{},<*0*>,<*1*>} by A3,ENUMSET1:14; suppose x in {{}}; then x = {} by TARSKI:def 1; hence x in {{},<*0*>,<*1*>} by ENUMSET1:14; end; hence x in {{},<*0*>,<*1*>}; end; hence thesis by A1,XBOOLE_0:def 2; end; theorem Th11: for Z being Tree,n,m st n <= m & <*m*> in Z holds <*n*> in Z proof let Z be Tree,n,m; assume n <= m & <*m*> in Z; then A1: {}^<*m*> in Z & n <= m by FINSEQ_1:47; reconsider s = {} as FinSequence of NAT by TREES_1:47; s^<*n*> in Z by A1,TREES_1:def 5; hence thesis by FINSEQ_1:47; end; theorem Th12: w^t is_a_proper_prefix_of w^s implies t is_a_proper_prefix_of s proof assume A1: w^t is_a_proper_prefix_of w^s; then w^t is_a_prefix_of w^s & w^t <> w^s by XBOOLE_0:def 8; then consider a be FinSequence such that A2: w^s = w^t^a by TREES_1:8; w^t^a = w^(t^a) by FINSEQ_1:45; then s= t^a by A2,FINSEQ_1:46; then t is_a_prefix_of s by TREES_1:8; hence thesis by A1,XBOOLE_0:def 8; end; theorem Th13: t1 in PFuncs(NAT*,[: NAT,NAT :]) proof A1: rng t1 c= [: NAT,NAT :] by TREES_2:def 9; dom t1 c= NAT* by TREES_1:def 5; hence thesis by A1,PARTFUN1:def 5; end; canceled; theorem Th15: for Z,Z1,Z2 being Tree,z being Element of Z st Z with-replacement (z,Z1) = Z with-replacement (z,Z2) holds Z1 = Z2 proof let Z,Z1,Z2 be Tree,z be Element of Z; assume A1: Z with-replacement (z,Z1) = Z with-replacement (z,Z2); now let s; thus s in Z1 implies s in Z2 proof assume A2: s in Z1; per cases; suppose s = {}; hence thesis by TREES_1:47; suppose s <> {}; then A3: z is_a_proper_prefix_of z^s by TREES_1:33; z^s in Z with-replacement (z,Z2) by A1,A2,TREES_1:def 12; then ex w st w in Z2 & z^s = z^w by A3,TREES_1:def 12; hence thesis by FINSEQ_1:46; end; assume A4: s in Z2; per cases; suppose s = {}; hence s in Z1 by TREES_1:47; suppose s <> {}; then A5: z is_a_proper_prefix_of z^s by TREES_1:33; z^s in Z with-replacement (z,Z1) by A1,A4,TREES_1:def 12; then ex w st w in Z1 & z^s = z^w by A5,TREES_1:def 12; hence s in Z1 by FINSEQ_1:46; end; hence thesis by TREES_2:def 1; end; theorem Th16: for Z,Z1,Z2 being DecoratedTree of D,z being Element of dom Z st Z with-replacement (z,Z1) = Z with-replacement (z,Z2) holds Z1 = Z2 proof let Z,Z1,Z2 be DecoratedTree of D,z be Element of dom Z; assume A1: Z with-replacement (z,Z1) = Z with-replacement (z,Z2); set T1 = Z with-replacement (z,Z1); set T2 = Z with-replacement (z,Z2); A2: dom T1 = dom Z with-replacement (z,dom Z1) by TREES_2:def 12; A3: dom T2 = dom Z with-replacement (z,dom Z2) by TREES_2:def 12; A4: dom Z with-replacement (z,dom Z1) = dom Z with-replacement (z,dom Z2) by A1,A2,TREES_2:def 12; A5: dom Z1 = dom Z2 by A1,A2,A3,Th15; for s st s in dom Z1 holds Z1.s = Z2.s proof let s; assume s in dom Z1; then A6: z^s in dom Z with-replacement (z,dom Z2) & z^s in dom Z with-replacement (z,dom Z1) by A4,TREES_1:def 12; A7: z is_a_prefix_of z^s by TREES_1:8; then consider w such that A8: w in dom Z2 & z^s = z^w & T2.(z^s) = Z2.w by A6,TREES_2:def 12; A9: ex u st u in dom Z1 & z^s = z^u & T1.(z^s) = Z1.u by A6,A7,TREES_2:def 12; s = w by A8,FINSEQ_1:46; hence thesis by A1,A8,A9,FINSEQ_1:46; end; hence thesis by A5,TREES_2:33; end; theorem Th17: for Z1,Z2 being Tree,p being FinSequence of NAT st p in Z1 holds for v being Element of Z1 with-replacement (p,Z2), w being Element of Z1 st v = w & w is_a_proper_prefix_of p holds succ v = succ w proof let Z1,Z2 be Tree,p be FinSequence of NAT; assume A1: p in Z1; set Z = Z1 with-replacement (p,Z2); let v be Element of Z,w be Element of Z1; assume A2: v = w & w is_a_proper_prefix_of p; then w is_a_prefix_of p & w <> p by XBOOLE_0:def 8; then consider r be FinSequence such that A3: p = w^r by TREES_1:8; now let n; assume A4: n in dom r; then A5: p.(len w + n) = r.n by A3,FINSEQ_1:def 7; len w + n in dom p by A3,A4,FINSEQ_1:41; then p.(len w + n) in rng p by FUNCT_1:def 5; hence r.n in NAT by A5; end; then reconsider r as FinSequence of NAT by FINSEQ_2:14; A6: r <> {} by A2,A3,FINSEQ_1:47; now let x; thus x in succ v implies x in succ w proof assume x in succ v; then x in { v^<*n*> : v^<*n*> in Z} by TREES_2:def 5; then consider n such that A7: x = v^<*n*> & v^<*n*> in Z; reconsider x' = x as FinSequence of NAT by A7; now per cases by A1,A7,TREES_1:def 12; suppose x' in Z1 & not p is_a_proper_prefix_of x'; then x in { w^<*m*> : w^<*m*> in Z1} by A2,A7; hence thesis by TREES_2:def 5; suppose ex r be FinSequence of NAT st r in Z2 & x' = p^r; then consider s such that A8: s in Z2 & v^<*n*> = p^s by A7; w^<*n*> = w^(r^s) by A2,A3,A8,FINSEQ_1:45; then A9: <*n*> = r^s by FINSEQ_1:46; s = {} proof assume not thesis; then len s <> 0 by FINSEQ_1:25; then len s > 0 by NAT_1:19; then A10: 0+1 <= len s by NAT_1:38; len r <> 0 by A6,FINSEQ_1:25; then len r > 0 by NAT_1:19; then 0+1 <= len r by NAT_1:38; then 1 + 1 <= len r + len s by A10,REAL_1:55; then 2 <= len (<*n*>) by A9,FINSEQ_1:35; then 2 <= 1 by FINSEQ_1:56; hence contradiction; end; then <*n*> = r by A9,FINSEQ_1:47; then x in { w^<*m*> : w^<*m*> in Z1} by A1,A2,A3,A7; hence thesis by TREES_2:def 5; end; hence thesis; end; assume x in succ w; then x in { w^<*n*> : w^<*n*> in Z1} by TREES_2:def 5; then consider n such that A11: x = w^<*n*> & w^<*n*> in Z1; now assume A12: not v^<*n*> in Z; now per cases by A1,A12,TREES_1:def 12; suppose not v^<*n*> in Z1; hence contradiction by A2,A11; suppose p is_a_proper_prefix_of v^<*n*>; then r is_a_proper_prefix_of <*n*> by A2,A3,Th12; then r in ProperPrefixes <*n*> by TREES_1:36; then r in{{}} by TREES_1:40; hence contradiction by A6,TARSKI:def 1; end; hence contradiction; end; then x in { v^<*m*> : v^<*m*> in Z} by A2,A11; hence x in succ v by TREES_2:def 5; end; hence thesis by TARSKI:2; end; theorem Th18: for Z1,Z2 being Tree,p being FinSequence of NAT st p in Z1 holds for v being Element of Z1 with-replacement (p,Z2),w being Element of Z1 st v = w & not p,w are_c=-comparable holds succ v = succ w proof let Z1,Z2 be Tree,p be FinSequence of NAT; assume A1: p in Z1; set Z = Z1 with-replacement (p,Z2); let v be Element of Z,w be Element of Z1; assume A2: v = w & not p,w are_c=-comparable; then A3: not w is_a_prefix_of p & not p is_a_prefix_of w by XBOOLE_0:def 9; now let x; thus x in succ v implies x in succ w proof assume x in succ v; then x in { v^<*n*> : v^<*n*> in Z} by TREES_2:def 5; then consider n such that A4: x = v^<*n*> & v^<*n*> in Z; reconsider x' = x as FinSequence of NAT by A4; v^<*n*> in Z1 proof assume A5: not v^<*n*> in Z1; then ex t st t in Z2 & x' = p^t by A1,A4,TREES_1:def 12; then A6: p is_a_prefix_of v^<*n*> by A4,TREES_1:8; per cases by A6,XBOOLE_0:def 8; suppose p is_a_proper_prefix_of v^<*n*>; hence contradiction by A2,A3,TREES_1:32; suppose p = v^<*n*>; hence contradiction by A1,A5; end; then x in { w^<*m*> : w^<*m*> in Z1} by A2,A4; hence thesis by TREES_2:def 5; end; assume x in succ w; then x in { w^<*n*> : w^<*n*> in Z1} by TREES_2:def 5 ; then consider n such that A7: x = w^<*n*> & w^<*n*> in Z1; not p is_a_proper_prefix_of w^<*n*> by A3,TREES_1:32; then v^<*n*> in Z by A1,A2,A7,TREES_1:def 12; then x in { v^<*m*> : v^<*m*> in Z} by A2,A7; hence x in succ v by TREES_2:def 5; end; hence thesis by TARSKI:2; end; theorem Th19: for Z1,Z2 being Tree,p being FinSequence of NAT st p in Z1 holds for v being Element of Z1 with-replacement (p,Z2),w being Element of Z2 st v = p^w holds succ v,succ w are_equipotent proof let Z1,Z2 be Tree,p be FinSequence of NAT such that A1: p in Z1; set T = Z1 with-replacement (p,Z2); let t be Element of Z1 with-replacement (p,Z2), t2 be Element of Z2; assume A2: t = p^t2; then A3: p is_a_prefix_of t by TREES_1:8; A4: for n holds t^<*n*> in T iff t2^<*n*> in Z2 proof let n; A5: p is_a_proper_prefix_of t^<*n*> by A3,TREES_1:31; A6: t^<*n*> = p^(t2^<*n*>) by A2,FINSEQ_1:45; thus t^<*n*> in T implies t2^<*n*> in Z2 proof assume t^<*n*> in T; then ex w st w in Z2 & t^<*n*> = p^w by A1,A5,TREES_1:def 12; hence thesis by A6,FINSEQ_1:46; end; assume t2^<*n*> in Z2; hence thesis by A1,A6,TREES_1:def 12; end; defpred P[set,set] means for n st $1 = t^<*n*> holds $2 = t2^<*n*>; A7: for x,y1,y2 st x in succ t & P[x,y1] & P[x,y2] holds y1 = y2 proof let x,y1,y2; assume A8: x in succ t & P[x,y1] & P[x,y2]; then x in { t^<*n*> : t^<*n*> in T } by TREES_2:def 5; then consider n such that A9: x = t^<*n*> & t^<*n*> in T; y1 = t2^<*n*> by A8,A9; hence thesis by A8,A9; end; A10: for x st x in succ t ex y st P[x,y] proof let x; assume x in succ t; then x in { t^<*n*> : t^<*n*> in T } by TREES_2:def 5; then consider n such that A11: x = t^<*n*> & t^<*n*> in T; take t2^<*n*>; let m; assume x = t^<*m*>; hence thesis by A11,FINSEQ_1:46; end; consider f being Function such that A12: dom f = succ t & for x st x in succ t holds P[x,f.x] from FuncEx(A7,A10); A13: rng f = succ t2 proof now let x; thus x in rng f implies x in succ t2 proof assume x in rng f; then consider y such that A14: y in dom f & x = f.y by FUNCT_1:def 5; y in { t^<*n*> : t^<*n*> in T } by A12,A14,TREES_2:def 5; then consider n such that A15: y = t^<*n*> & t^<*n*> in T; A16: x = t2^<*n*> by A12,A14,A15; t2^<*n*> in Z2 by A4,A15; then x in { t2^<*m*> : t2^<*m*> in Z2 } by A16; hence thesis by TREES_2:def 5; end; assume x in succ t2; then x in { t2^<*n*> : t2^<*n*> in Z2 } by TREES_2:def 5; then consider n such that A17: x = t2^<*n*> & t2^<*n*> in Z2; t^<*n*> in T by A4,A17; then t^<*n*> in { t^<*m*> : t^<*m*> in T }; then A18: t^<*n*> in dom f by A12,TREES_2:def 5; then f.(t^<*n*>) = x by A12,A17; hence x in rng f by A18,FUNCT_1:def 5; end; hence thesis by TARSKI:2; end; f is one-to-one proof now let x1,x2; assume A19: x1 in dom f & x2 in dom f & f.x1 = f.x2; then x1 in { t^<*n*> : t^<*n*> in T } by A12,TREES_2:def 5; then consider m such that A20: x1 = t^<*m*> & t^<*m*> in T; x2 in { t^<*n*> : t^<*n*> in T } by A12,A19,TREES_2:def 5; then consider k such that A21: x2 = t^<*k*> & t^<*k*> in T; t2^<*m*> = f.x1 by A12,A19,A20 .= t2^<*k*> by A12,A19,A21; hence x1 = x2 by A20,A21,FINSEQ_1:46; end; hence thesis by FUNCT_1:def 8; end; hence thesis by A12,A13,WELLORD2:def 4; end; theorem Th20: for Z1 being Tree,p being FinSequence of NAT st p in Z1 holds for v being Element of Z1,w being Element of Z1|p st v = p^w holds succ v,succ w are_equipotent proof let Z1 be Tree,p be FinSequence of NAT such that A1: p in Z1; set T = Z1|p; let t be Element of Z1,t2 be Element of Z1|p such that A2: t = p^t2; A3: for n holds t^<*n*> in Z1 iff t2^<*n*> in T proof let n; A4: t^<*n*> = p^(t2^<*n*>) by A2,FINSEQ_1:45; hence t^<*n*> in Z1 implies t2^<*n*> in T by A1,TREES_1:def 9; assume t2^<*n*> in T; hence thesis by A1,A4,TREES_1:def 9; end; defpred P[set,set] means for n st $1 = t^<*n*> holds $2 = t2^<*n*>; A5: for x,y1,y2 st x in succ t & P[x,y1] & P[x,y2] holds y1 = y2 proof let x,y1,y2; assume A6: x in succ t & P[x,y1] & P[x,y2]; then x in { t^<*n*> : t^<*n*> in Z1 } by TREES_2:def 5; then consider n such that A7: x = t^<*n*> & t^<*n*> in Z1; y1 = t2^<*n*> by A6,A7; hence thesis by A6,A7; end; A8: for x st x in succ t ex y st P[x,y] proof let x; assume x in succ t; then x in { t^<*n*> : t^<*n*> in Z1 } by TREES_2:def 5; then consider n such that A9: x = t^<*n*> & t^<*n*> in Z1; take t2^<*n*>; let m; assume x = t^<*m*>; hence thesis by A9,FINSEQ_1:46; end; consider f being Function such that A10: dom f = succ t & for x st x in succ t holds P[x,f.x] from FuncEx(A5,A8); A11: rng f = succ t2 proof now let x; thus x in rng f implies x in succ t2 proof assume x in rng f; then consider y such that A12: y in dom f & x = f.y by FUNCT_1:def 5; y in { t^<*n*> : t^<*n*> in Z1 } by A10,A12,TREES_2:def 5; then consider n such that A13: y = t^<*n*> & t^<*n*> in Z1; A14: x = t2^<*n*> by A10,A12,A13; t2^<*n*> in T by A3,A13; then x in { t2^<*m*> : t2^<*m*> in T } by A14; hence thesis by TREES_2:def 5; end; assume x in succ t2; then x in { t2^<*n*> : t2^<*n*> in T } by TREES_2:def 5; then consider n such that A15: x = t2^<*n*> & t2^<*n*> in T; t^<*n*> in Z1 by A3,A15; then t^<*n*> in { t^<*m*> : t^<*m*> in Z1 }; then A16: t^<*n*> in dom f by A10,TREES_2:def 5; then f.(t^<*n*>) = x by A10,A15; hence x in rng f by A16,FUNCT_1:def 5; end; hence thesis by TARSKI:2; end; f is one-to-one proof now let x1,x2; assume A17: x1 in dom f & x2 in dom f & f.x1 = f.x2; then x1 in { t^<*n*> : t^<*n*> in Z1 } by A10,TREES_2:def 5; then consider m such that A18: x1 = t^<*m*> & t^<*m*> in Z1; x2 in { t^<*n*> : t^<*n*> in Z1 } by A10,A17,TREES_2:def 5; then consider k such that A19: x2 = t^<*k*> & t^<*k*> in Z1; t2^<*m*> = f.x1 by A10,A17,A18 .= t2^<*k*> by A10,A17,A19; hence x1 = x2 by A18,A19,FINSEQ_1:46; end; hence thesis by FUNCT_1:def 8; end; hence thesis by A10,A11,WELLORD2:def 4; end; canceled; theorem Th22: for Z being finite Tree st branchdeg (Root Z) = 0 holds card Z = 1 & Z = {{}} proof let Z be finite Tree; assume branchdeg (Root Z) = 0; then 0 = card succ (Root Z) by PRELAMB:def 4; then A1: succ (Root Z) = {} by CARD_2:59; Z = { Root Z } proof now let x; thus x in Z implies x in { Root Z } proof assume x in Z; then reconsider z = x as Element of Z; assume not thesis; then z <> Root Z by TARSKI:def 1; then z <> {} by Def1; then consider w,n such that A2: z = <*n*>^w by Th4; <*n*> is_a_prefix_of z by A2,TREES_1:8; then <*n*> in Z by TREES_1:45; then {}^<*n*> in Z by FINSEQ_1:47; then (Root Z)^<*n*> in Z by Def1; hence contradiction by A1,TREES_2:14; end; assume x in { Root Z }; then reconsider x'= x as Element of Z; x' in Z; hence x in Z; end; hence thesis by TARSKI:2; end; hence thesis by Def1,CARD_2:60; end; theorem Th23: for Z being finite Tree st branchdeg (Root Z) = 1 holds succ (Root Z) = { <*0*> } proof let Z be finite Tree; assume branchdeg (Root Z) = 1; then card succ (Root Z) = 1 by PRELAMB:def 4; then consider x such that A1: succ (Root Z) = {x} by CARD_2:60; A2: x in succ (Root Z) by A1,TARSKI:def 1; then reconsider x' = x as Element of Z; x' in { (Root Z)^<*n*> : (Root Z)^<*n*> in Z } by A2,TREES_2:def 5; then consider m such that A3: x' = (Root Z)^<*m*> & (Root Z)^<*m*> in Z; A4: x' = {}^<*m*> by A3,Def1 .= <*m*> by FINSEQ_1:47; now assume A5: m <> 0; <*m*> in Z & 0 <= m by A4,NAT_1:18; then A6: <*0*> in Z by Th11; A7: <*0*> = {}^<*0*> by FINSEQ_1:47 .= (Root Z)^<*0*> by Def1; then (Root Z)^<*0*> in succ (Root Z) by A6,TREES_2:14; then <*0*> = x by A1,A7,TARSKI:def 1; hence contradiction by A4,A5,TREES_1:16; end; hence thesis by A1,A4; end; theorem Th24: for Z being finite Tree st branchdeg (Root Z) = 2 holds succ (Root Z) = { <*0*>,<*1*> } proof let Z be finite Tree; assume branchdeg (Root Z) = 2; then card succ (Root Z) = 2 by PRELAMB:def 4; then consider x,y such that A1: x <> y & succ (Root Z) = {x,y} by GROUP_3:166; A2: x in succ (Root Z) & y in succ (Root Z) by A1,TARSKI:def 2; then reconsider x' = x as Element of Z; reconsider y' = y as Element of Z by A2; x' in { (Root Z)^<*n*> : (Root Z)^<*n*> in Z } by A2,TREES_2:def 5; then consider m such that A3: x' = (Root Z)^<*m*> & (Root Z)^<*m*> in Z; A4: x' = {}^<*m*> by A3,Def1 .= <*m*> by FINSEQ_1:47; y' in { (Root Z)^<*n*> : (Root Z)^<*n*> in Z } by A2,TREES_2:def 5; then consider k such that A5: y' = (Root Z)^<*k*> & (Root Z)^<*k*> in Z; A6: y' = {}^<*k*> by A5,Def1 .= <*k*> by FINSEQ_1:47; per cases; suppose A7: m = 0; now assume A8: k <> 1; then 2 <= k by A1,A4,A6,A7,CQC_THE1:3; then 1 <= k by AXIOMS:22; then A9: <*1*> in Z by A6,Th11; <*1*> = {}^<*1*> by FINSEQ_1:47 .= (Root Z)^<*1*> by Def1; then <*1*> in succ (Root Z) by A9,TREES_2:14; then <*1*> = <*0*> or <*1*> = <*k*> by A1,A4,A6,A7,TARSKI:def 2; hence contradiction by A8,TREES_1:16; end; hence thesis by A1,A4,A6,A7; suppose A10: m <> 0; 0 <= m by NAT_1:18; then A11: <*0*> in Z by A4,Th11; <*0*> = {}^<*0*> by FINSEQ_1:47 .= (Root Z)^<*0*> by Def1; then <*0*> in succ (Root Z) by A11,TREES_2:14; then A12: <*0*> = <*m*> or <*0*> = <*k*> by A1,A4,A6,TARSKI:def 2; now assume A13: m <> 1; then 2 <= m by A10,CQC_THE1:3; then 1 <= m by AXIOMS:22; then A14: <*1*> in Z by A4,Th11; <*1*> = {}^<*1*> by FINSEQ_1:47 .= (Root Z)^<*1*> by Def1; then <*1*> in succ (Root Z) by A14,TREES_2:14; then <*1*> = <*0*> or <*1*> = <*m*> by A1,A4,A6,A10,A12,TARSKI:def 2,TREES_1:16; hence contradiction by A13,TREES_1:16; end; hence thesis by A1,A4,A6,A12,TREES_1:16; end; reserve s',w',v' for Element of NAT*; theorem Th25: for Z being Tree,o being Element of Z st o <> Root Z holds Z|o,{ o^s': o^s' in Z } are_equipotent & not Root Z in { o^w' : o^w' in Z } proof let Z be Tree,o be Element of Z such that A1: o <> Root Z; set A = { o^s' : o^s' in Z }; thus Z|o,A are_equipotent proof defpred P[set,set] means for s st $1 = s holds $2 = o^s; A2: for x,y1,y2 st x in Z|o & P[x,y1] & P[x,y2] holds y1 = y2 proof let x,y1,y2; assume A3: x in Z|o & P[x,y1] & P[x,y2]; then reconsider s = x as FinSequence of NAT by TREES_1:44; y1 = o^s & y2 = o^s by A3; hence thesis; end; A4: for x st x in Z|o ex y st P[x,y] proof let x; assume x in Z|o; then reconsider s = x as FinSequence of NAT by TREES_1:44; take o^s; let w; assume x = w; hence thesis; end; ex f being Function st dom f = Z|o & for x st x in Z|o holds P[x,f.x] from FuncEx(A2,A4); then consider f being Function such that A5: dom f = Z|o and A6: for x st x in Z|o holds for s st x = s holds f.x = o^s; A7: rng f = A proof now let x; thus x in rng f implies x in A proof assume x in rng f; then consider x1 such that A8: x1 in dom f & x = f.x1 by FUNCT_1:def 5; reconsider x1 as FinSequence of NAT by A5,A8,TREES_1:44; reconsider x1 as Element of NAT* by FINSEQ_1:def 11; A9: o^x1 in Z by A5,A8,TREES_1:def 9; x = o^x1 & x1 is Element of NAT* by A5,A6,A8; hence x in A by A9; end; assume x in A; then consider v' such that A10: x = o^v' & o^v' in Z; A11: v' in Z|o by A10,TREES_1:def 9; A12: v' in dom f by A5,A10,TREES_1:def 9; x = f.v' by A6,A10,A11; hence x in rng f by A12,FUNCT_1:def 5; end; hence thesis by TARSKI:2; end; f is one-to-one proof now let x1,x2; assume A13: x1 in dom f & x2 in dom f & f.x1 = f.x2; then reconsider s1 = x1, s2 = x2 as FinSequence of NAT by A5,TREES_1:44 ; o^s1 = f.x2 by A5,A6,A13 .= o^s2 by A5,A6,A13; hence x1 = x2 by FINSEQ_1:46; end; hence thesis by FUNCT_1:def 8; end; hence thesis by A5,A7,WELLORD2:def 4; end; assume not thesis; then consider v' such that A14: Root Z = o^v' & o^v' in Z; {} = o^v' by A14,Def1; then o = {} by FINSEQ_1:48; hence contradiction by A1,Def1; end; theorem Th26: for Z being finite Tree,o being Element of Z st o <> Root Z holds card (Z|o) < card Z proof let Z be finite Tree,o be Element of Z such that A1: o <> Root Z; set A = { o^s' : o^s' in Z }; A2: Z|o,A are_equipotent & not Root Z in A by A1,Th25; then reconsider A as finite set by CARD_1:68; reconsider B = A \/ {Root Z} as finite set; A3: card B = card A + 1 by A2,CARD_2:54 .= card (Z|o) + 1 by A2,CARD_1:81; B c= Z proof now let x such that A4: x in B; now per cases by A4,XBOOLE_0:def 2; suppose x in { o^s' : o^s' in Z }; then ex v' st x = o^v' & o^v' in Z; hence x in Z; suppose x in {Root Z}; hence x in Z; end; hence x in Z; end; hence thesis by TARSKI:def 3; end; then card (Z|o) + 1 <= card Z by A3,CARD_1:80; hence thesis by NAT_1:38; end; theorem Th27: for Z being finite Tree,z being Element of Z st succ (Root Z) = {z} holds Z = elementary_tree 1 with-replacement (<*0*>,Z|z) proof set e = elementary_tree 1; A1: <*0*> in e by Th9,TARSKI:def 2; let Z be finite Tree,z be Element of Z; assume A2: succ (Root Z) = {z}; then card succ (Root Z) = 1 by CARD_1:79; then branchdeg (Root Z) = 1 by PRELAMB:def 4; then {z} = { <*0*> } by A2,Th23; then z in { <*0*> } by TARSKI:def 1; then A3: z = <*0*> by TARSKI:def 1; then A4: <*0*> in Z; A5: {} in Z by TREES_1:47; now let x; thus x in Z implies x in e with-replacement (<*0*>,Z|z) proof assume x in Z; then reconsider x' = x as Element of Z; per cases; suppose x' = {}; hence x in e with-replacement (<*0*>,Z|z) by TREES_1:47; suppose x' <> {}; then consider w,n such that A6: x' = <*n*>^w by Th4; <*n*> is_a_prefix_of x' by A6,TREES_1:8; then A7: <*n*> in Z by TREES_1:45; <*n*> = {}^<*n*> by FINSEQ_1:47 .= (Root Z)^<*n*> by Def1; then A8: <*n*> in succ (Root Z) by A7,TREES_2:14; then A9: <*n*> = <*0*> by A2,A3,TARSKI:def 1; <*n*> = z by A2,A8,TARSKI:def 1; then w in Z|z by A6,TREES_1:def 9; hence x in e with-replacement (<*0*>,Z|z) by A1,A6,A9,TREES_1:def 12; end; assume x in e with-replacement (<*0*>,Z|z); then reconsider x' = x as Element of e with-replacement (<*0*>,Z|z); per cases by A1,TREES_1:def 12; suppose x' in e & not <*0*> is_a_proper_prefix_of x'; hence x in Z by A4,A5,Th9,TARSKI:def 2; suppose ex s st s in Z|z & x' = <*0*>^s; hence x in Z by A3,TREES_1:def 9; end; hence thesis by TARSKI:2; end; Lm2: for f being Function st dom f is finite holds f is finite proof let f be Function; assume A1: dom f is finite; then rng f is finite by FINSET_1:26; then A2: [:dom f, rng f:] is finite by A1,FINSET_1:19; f c= [:dom f, rng f:] by RELAT_1:21; hence f is finite by A2,FINSET_1:13; end; theorem Th28: for Z being finite DecoratedTree of D,z be Element of dom Z st succ (Root dom Z) = {z} & dom Z is finite holds Z = ((elementary_tree 1) --> Root Z) with-replacement (<*0*>,Z|z) proof let Z be finite DecoratedTree of D,z be Element of dom Z; assume A1: succ (Root dom Z) = {z} & dom Z is finite; then card succ (Root dom Z) = 1 by CARD_1:79; then branchdeg (Root dom Z) = 1 by PRELAMB:def 4; then {z} = { <*0*> } by A1,Th23; then z in { <*0*> } by TARSKI:def 1; then A2: z = <*0*> by TARSKI:def 1; set e = elementary_tree 1; set E = (elementary_tree 1) --> Root Z; A3: <*0*> in e by Th9,TARSKI:def 2; A4: dom E = e & rng E = { Root Z } by FUNCOP_1:14,19; A5: <*0*> in dom E by A3,FUNCOP_1:19; A6: dom (Z|z) = (dom Z)|z by TREES_2:def 11; then dom (E with-replacement (<*0*>,Z|z)) = e with-replacement (<*0*>, (dom Z)|z) by A3,A4,TREES_2:def 12; then A7: dom (E with-replacement (<*0*>,Z|z)) = dom Z by A1,Th27; for s st s in dom (E with-replacement (<*0*>,Z|z)) holds (E with-replacement (<*0*>,Z|z)).s = Z.s proof A8: dom (E with-replacement (<*0*>,Z|z)) = dom E with-replacement(<*0*>,dom (Z|z)) by A5,TREES_2:def 12; let s; assume A9: s in dom (E with-replacement (<*0*>,Z|z)); then A10: not <*0*> is_a_prefix_of s & (E with-replacement (<*0*>,Z|z)).s = E.s or ex w st w in dom (Z|z) & s = <*0*>^w & (E with-replacement (<*0*>,Z|z)).s = (Z|z).w by A5,A8,TREES_2:def 12; now per cases by A5,A8,A9,TREES_1:def 12; suppose A11: s in dom E & not <*0*> is_a_proper_prefix_of s; now per cases by A4,A11,Th9,TARSKI:def 2; suppose A12: s = {}; then A13: s in e by TREES_1:47; A14: now given w such that A15: w in dom (Z|z) & s = <*0*>^w & (E with-replacement (<*0*>,Z|z)).s = (Z|z).w; <*0*> = {} & w = {} by A12,A15,FINSEQ_1:48; hence contradiction by TREES_1:4; end; E.s = Root Z by A13,FUNCOP_1:13 .= Z.(Root dom Z) by Def2 .= Z.s by A12,Def1; hence thesis by A5,A8,A9,A14,TREES_2:def 12; suppose s = <*0*>; hence thesis by A2,A6,A10,TREES_2:def 11; end; hence thesis; suppose ex w st w in dom (Z|z) & s = <*0*>^w; hence thesis by A2,A6,A10,TREES_1:8,TREES_2:def 11; end; hence thesis; end; hence thesis by A7,TREES_2:33; end; theorem Th29: for Z being Tree,x1,x2 be Element of Z st Z is finite & x1 = <*0*> & x2 = <*1*> & succ (Root Z) = {x1,x2} holds Z = (elementary_tree 2 with-replacement (<*0*>,Z|x1)) with-replacement (<*1*>,Z|x2) proof set e = elementary_tree 2; A1: <*0*> in e & <*1*> in e by Th10,ENUMSET1:14; let Z be Tree,x1,x2 be Element of Z such that Z is finite and A2: x1 = <*0*> & x2 = <*1*> & succ (Root Z) = {x1,x2}; set T1 = elementary_tree 2 with-replacement (<*0*>,Z|x1); A3: <*1*> in T1 proof now assume <*0*> is_a_proper_prefix_of <*1*>; then <*0*> is_a_prefix_of <*1*> by XBOOLE_0:def 8; hence contradiction by TREES_1:16; end; hence thesis by A1,TREES_1:def 12; end; now let s; thus s in Z implies s in T1 & not <*1*> is_a_proper_prefix_of s or ex w st w in Z|x2 & s = <*1*>^w proof assume A4: s in Z; per cases; suppose s = {}; hence thesis by TREES_1:36,39,47; suppose s <> {}; then consider w,n such that A5: s = <*n*>^w by Th4; <*n*> is_a_prefix_of s by A5,TREES_1:8; then A6: <*n*> in Z by A4,TREES_1:45; <*n*> = {}^<*n*> by FINSEQ_1:47 .= (Root Z)^<*n*> by Def1; then A7: <*n*> in succ (Root Z) by A6,TREES_2:14; now per cases by A2,A7,TARSKI:def 2; suppose A8: <*n*> = <*0*>; then w in Z|x1 by A2,A4,A5,TREES_1:def 9; hence thesis by A1,A5,A8,Th5,TREES_1:def 12; suppose A9: <*n*> = <*1*>; then w in Z|x2 by A2,A4,A5,TREES_1:def 9; hence thesis by A5,A9; end; hence thesis; end; assume A10: s in T1 & not <*1*> is_a_proper_prefix_of s or ex w st w in Z|x2 & s = <*1*>^w; now per cases by A10; suppose A11: s in T1 & not <*1*> is_a_proper_prefix_of s; now per cases by A1,A11,TREES_1:def 12; suppose s in e & not <*0*> is_a_proper_prefix_of s; then s = {} or s = <*0*> or s = <*1*> by Th10,ENUMSET1:13; hence s in Z by A2,TREES_1:47; suppose ex w st w in Z|x1 & s = <*0*>^w; hence s in Z by A2,TREES_1:def 9; end; hence s in Z; suppose ex w st w in Z|x2 & s = <*1*>^w; hence s in Z by A2,TREES_1:def 9; end; hence s in Z; end; hence thesis by A3,TREES_1:def 12; end; theorem Th30: for Z being DecoratedTree of D,x1,x2 being Element of dom Z st dom Z is finite & x1 = <*0*> & x2 = <*1*> & succ (Root dom Z) = {x1,x2} holds Z = (((elementary_tree 2) --> Root Z) with-replacement (<*0*>, Z|x1)) with-replacement (<*1*>,Z|x2) proof let Z be DecoratedTree of D,x1,x2 be Element of dom Z such that A1: dom Z is finite & x1 = <*0*> & x2 = <*1*> & succ (Root dom Z) = {x1,x2}; set e = elementary_tree 2; set E = (elementary_tree 2) --> Root Z; A2: <*0*> in e & <*1*> in e by Th10,ENUMSET1:14; A3: dom E = e by FUNCOP_1:19; A4: <*0*> in dom E & <*1*> in dom E by A2,FUNCOP_1:19; A5: dom (Z|x1) = (dom Z)|x1 & dom (Z|x2) = (dom Z)|x2 by TREES_2:def 11; set T1 = ((elementary_tree 2) --> Root Z) with-replacement (<*0*>,Z|x1); set T = T1 with-replacement (<*1*>,Z|x2); A6: dom T1 = dom E with-replacement (<*0*>,dom (Z|x1)) by A4,TREES_2:def 12; A7: dom T1 = e with-replacement (<*0*>,(dom Z)|x1) by A2,A3,A5,TREES_2:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A8: <*1*> in dom T1 by A4,A6,TREES_1:def 12; then A9: dom T = dom T1 with-replacement (<*1*>,dom (Z|x2)) by TREES_2:def 12 ; then A10: dom Z = dom T by A1,A3,A5,A6,Th29; for s st s in dom T holds T.s = Z.s proof let s; assume A11: s in dom T; then A12: not <*1*> is_a_prefix_of s & T.s = T1.s or ex u st u in dom(Z|x2) & s = <*1*>^u & T.s = (Z|x2).u by A8,A9,TREES_2:def 12; now per cases by A8,A9,A11,TREES_1:def 12; suppose A13: s in dom T1 & not <*1*> is_a_proper_prefix_of s; then A14: not <*0*> is_a_prefix_of s & T1.s = E.s or ex u st u in dom(Z|x1) & s = <*0*>^u & T1.s = (Z|x1).u by A4,A6,TREES_2:def 12; now per cases by A2,A7,A13,TREES_1:def 12; suppose A15: s in e & not <*0*> is_a_proper_prefix_of s; now per cases by A15,Th10,ENUMSET1:13; suppose A16: s = {}; A17: now given u such that A18: u in dom (Z|x1) & s = <*0*>^u & T1.s = (Z|x1).u; <*0*> = {} by A16,A18,FINSEQ_1:48; hence contradiction by TREES_1:4; end; A19: now given u such that A20: u in dom(Z|x2) & s = <*1*>^u & T.s = (Z|x2).u; <*1*> = {} by A16,A20,FINSEQ_1:48; hence contradiction by TREES_1:4; end; E.s = Root Z by A15,FUNCOP_1:13 .= Z.(Root dom Z) by Def2 .= Z.s by A16,Def1; hence thesis by A8,A9,A11,A14,A17,A19,TREES_2:def 12; suppose s = <*0*>; hence thesis by A1,A5,A12,A14,TREES_2:def 11; suppose s = <*1*>; hence thesis by A1,A5,A12,TREES_2:def 11; end; hence thesis; suppose ex w st w in (dom Z)|x1 & s = <*0*>^w; hence thesis by A1,A5,A12,A14,TREES_1:8,TREES_2:def 11; end; hence thesis; suppose ex w st w in dom (Z|x2) & s = <*1*>^w; hence thesis by A1,A5,A12,TREES_1:8,TREES_2:def 11; end; hence thesis; end; hence thesis by A10,TREES_2:33; end; definition func MP-variables -> set equals :Def3: [: {3},NAT :]; coherence; end; definition cluster MP-variables -> non empty; coherence by Def3; end; definition mode MP-variable is Element of MP-variables; end; definition func MP-conectives -> set equals :Def4: [: {0,1,2},NAT :]; coherence; end; definition cluster MP-conectives -> non empty; coherence proof reconsider X = {0,1,2} as non empty set by ENUMSET1:14; [: X,NAT :] is non empty set; hence thesis by Def4; end; end; definition mode MP-conective is Element of MP-conectives; end; theorem Th31: MP-conectives misses MP-variables proof assume not thesis; then consider x being set such that A1: x in [:{0,1,2},NAT:] & x in [:{3},NAT:] by Def3,Def4,XBOOLE_0:3; consider x1,x2 such that A2: x1 in {0,1,2} & x2 in NAT & x = [x1,x2] by A1,ZFMISC_1:def 2; x1 = 3 by A1,A2,ZFMISC_1:128; hence contradiction by A2,ENUMSET1:13; end; reserve p,q for MP-variable; definition let T be finite Tree,v be Element of T; redefine func branchdeg v -> Nat; coherence proof branchdeg v = card succ v by PRELAMB:def 4; hence thesis; end; end; definition let D be non empty set; mode DOMAIN_DecoratedTree of D -> non empty set means :Def5: for x st x in it holds x is DecoratedTree of D; existence proof consider d being Element of D; take Z = {(elementary_tree 0) --> d}; let x; assume x in Z; hence thesis by TARSKI:def 1; end; end; definition let D0 be non empty set,D be DOMAIN_DecoratedTree of D0; redefine mode Element of D -> DecoratedTree of D0; coherence by Def5; end; definition func MP-WFF -> DOMAIN_DecoratedTree of [: NAT,NAT :] means :Def6: (for x being DecoratedTree of [: NAT,NAT :] st x in it holds x is finite) & for x being finite DecoratedTree of [: NAT,NAT :] holds x in it iff for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]); existence proof set A = [:NAT,NAT:]; defpred P[set] means $1 is finite DecoratedTree of A & (for y being finite DecoratedTree of A st y = $1 holds dom y is finite & for v being Element of dom y holds branchdeg v <= 2 & (branchdeg v = 0 implies y.v = [0,0] or ex k st y.v = [3,k]) & (branchdeg v = 1 implies y.v = [1,0] or y.v = [1,1]) & (branchdeg v = 2 implies y.v = [2,0])); consider Y being set such that A1: for x holds x in Y iff x in PFuncs(NAT*,A) & P[x] from Separation; A2: for x being finite DecoratedTree of A holds x in Y iff dom x is finite & for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) proof let x be finite DecoratedTree of A; thus x in Y implies dom x is finite & for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) by A1; assume dom x is finite & for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]); then A3: for y being finite DecoratedTree of A st y = x holds dom y is finite & for v being Element of dom y holds branchdeg v <= 2 & (branchdeg v = 0 implies y.v = [0,0] or ex k st y.v = [3,k]) & (branchdeg v = 1 implies y.v = [1,0] or y.v = [1,1]) & (branchdeg v = 2 implies y.v = [2,0]); x in PFuncs(NAT*,A) by Th13; hence thesis by A1,A3; end; set t=elementary_tree 0; deffunc F(set)=[0,0]; consider T being DecoratedTree such that A4: dom T = t & for p being FinSequence of NAT st p in t holds T.p=F(p) from DTreeLambda; rng T c= A proof let x; assume x in rng T; then consider z being set such that A5: z in dom T & x = T.z by FUNCT_1:def 5; z = {} by A4,A5,TARSKI:def 1,TREES_1:56; then reconsider z as FinSequence of NAT by FINSEQ_1:29; T.z = [0,0] by A4,A5; hence thesis by A5; end; then reconsider T as finite DecoratedTree of A by A4,Lm2,TREES_2:def 9; A6: T in PFuncs(NAT*,A) by Th13; for y being finite DecoratedTree of A st y = T holds dom y is finite & for v being Element of dom y holds branchdeg v <= 2 & (branchdeg v = 0 implies y.v = [0,0] or ex k st y.v = [3,k]) & (branchdeg v = 1 implies y.v = [1,0] or y.v = [1,1]) & (branchdeg v = 2 implies y.v = [2,0]) proof let y be finite DecoratedTree of A; assume A7: y = T; thus dom y is finite; let v be Element of dom y; A8: v = {} by A4,A7,TARSKI:def 1,TREES_1:56; A9: succ v = {} proof A10: succ v = { v^<*n*>: v^<*n*> in dom y } by TREES_2:def 5; assume A11: not thesis; consider x being Element of succ v; x in succ v by A11; then consider n such that A12: x = v^<*n*> & v^<*n*> in dom y by A10; A13: x = {} by A4,A7,A12,TARSKI:def 1,TREES_1:56; x = <*n*> by A8,A12,FINSEQ_1:47; hence contradiction by A13,TREES_1:4; end; then branchdeg v = 0 by CARD_1:78,PRELAMB:def 4; hence branchdeg v <= 2; thus thesis by A4,A7,A9,CARD_1:78,PRELAMB:def 4; end; then reconsider Y as non empty set by A1,A6; for x st x in Y holds x is DecoratedTree of A by A1; then reconsider Y as DOMAIN_DecoratedTree of A by Def5; take Y; thus thesis by A1,A2; end; uniqueness proof let D1,D2 be DOMAIN_DecoratedTree of [:NAT,NAT:] such that A14: for x being DecoratedTree of [: NAT,NAT :] st x in D1 holds x is finite and A15: for x being finite DecoratedTree of [:NAT,NAT:] holds x in D1 iff for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) and A16: for x being DecoratedTree of [: NAT,NAT :] st x in D2 holds x is finite and A17: for x being finite DecoratedTree of [:NAT,NAT:] holds x in D2 iff for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]); thus D1 c= D2 proof let x; assume A18: x in D1; then x is DecoratedTree of [:NAT,NAT:] by Def5; then reconsider y=x as finite DecoratedTree of [:NAT,NAT:] by A14,A18; dom y is finite & for v being Element of dom y holds branchdeg v <= 2 & (branchdeg v = 0 implies y.v = [0,0] or ex k st y.v = [3,k]) & (branchdeg v = 1 implies y.v = [1,0] or y.v = [1,1]) & (branchdeg v = 2 implies y.v = [2,0]) by A15,A18; hence thesis by A17; end; let x; assume A19: x in D2; then x is DecoratedTree of [:NAT,NAT:] by Def5; then reconsider y=x as finite DecoratedTree of [:NAT,NAT:] by A16,A19; dom y is finite & for v being Element of dom y holds branchdeg v <= 2 & (branchdeg v = 0 implies y.v = [0,0] or ex k st y.v = [3,k]) & (branchdeg v = 1 implies y.v = [1,0] or y.v = [1,1]) & (branchdeg v = 2 implies y.v = [2,0]) by A17,A19; hence thesis by A15; end; end; :: [0,0] = VERUM :: [1,0] = negation :: [1,1] = modal operator of necessity :: [2,0] = & definition mode MP-wff is Element of MP-WFF; end; definition cluster -> finite MP-wff; coherence by Def6; end; reserve A,A1,B,B1,C,C1 for MP-wff; definition let A; let a be Element of dom A; redefine func A|a -> MP-wff; coherence proof set x = A|a; A1: dom x = (dom A)|a by TREES_2:def 11; then reconsider db = dom x as finite Tree; reconsider x as finite DecoratedTree of [: NAT,NAT :] by A1,Lm2; now set da = dom A; thus db is finite; let v be Element of db; v in db; then A2: v in da|a by TREES_2:def 11; then reconsider w = a^v as Element of da by TREES_1:def 9; reconsider v' = v as Element of da|a by TREES_2:def 11; A3: succ w,succ v' are_equipotent by Th20; succ v' = succ v by TREES_2:def 11; then card succ v = card succ w by A3,CARD_1:81; then branchdeg v = card succ w by PRELAMB:def 4; then A4: branchdeg v = branchdeg w by PRELAMB:def 4; hence branchdeg v <= 2 by Def6; thus branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k] proof assume A5: branchdeg v = 0; per cases by A4,A5,Def6; suppose A.w = [0,0]; hence thesis by A2,TREES_2:def 11; suppose ex k st A.w = [3,k]; then consider k such that A6: A.w = [3,k]; now take k; thus x .v = [3,k] by A2,A6,TREES_2:def 11; end; hence thesis; end; thus branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1] proof assume A7: branchdeg v = 1; per cases by A4,A7,Def6; suppose A.w = [1,0]; hence thesis by A2,TREES_2:def 11; suppose A.w = [1,1]; hence thesis by A2,TREES_2:def 11; end; thus branchdeg v = 2 implies x .v = [2,0] proof assume branchdeg v = 2; then A.w = [2,0] by A4,Def6; hence x .v = [2,0] by A2,TREES_2:def 11; end; end; hence thesis by Def6; end; end; definition let a be Element of MP-conectives; func the_arity_of a -> Nat equals a`1; coherence proof reconsider X = {0,1,2} as non empty set by ENUMSET1:14; consider a1 being Element of X,k being Element of NAT such that A1: a=[a1,k] by Def4,DOMAIN_1:9; a1 = 0 or a1 = 1 or a1 = 2 by ENUMSET1:13; hence thesis by A1,MCART_1:7; end; end; definition let D be non empty set, T,T1 be DecoratedTree of D, p be FinSequence of NAT; assume A1: p in dom T; func @(T,p,T1) -> DecoratedTree of D equals :Def8: T with-replacement (p,T1); coherence proof set X = T with-replacement (p,T1); rng X c= D proof let x; assume x in rng X; then consider z being set such that A2: z in dom X & x = X.z by FUNCT_1: def 5; A3: dom X = dom T with-replacement (p,dom T1) by A1,TREES_2:def 12; reconsider z as FinSequence of NAT by A2,TREES_1:44; now per cases by A1,A2,A3,TREES_2:def 12; suppose A4: not p is_a_prefix_of z & X.z = T.z; then not ex s being FinSequence of NAT st s in dom T1 & z = p^s by TREES_1:8; then reconsider z as Element of dom T by A1,A2,A3,TREES_1:def 12; T.z is Element of D; hence x in D by A2,A4; suppose ex s st s in dom T1 & z = p^s & X.z = T1.s; then consider s such that A5: s in dom T1 & z = p^s & X.z = T1.s; reconsider s as Element of dom T1 by A5; T1.s is Element of D; hence x in D by A2,A5; end; hence thesis; end; hence X is DecoratedTree of D by TREES_2:def 9; end; end; theorem Th32: ((elementary_tree 1) --> [1,0]) with-replacement (<*0*>,A) is MP-wff proof set x = ((elementary_tree 1) --> [1,0]) with-replacement (<*0*>,A); A1: <*0*> in dom ((elementary_tree 1) --> [1,0]) proof <*0*> in elementary_tree 1 by TREES_1:55; hence thesis by FUNCOP_1:19; end; then A2: dom x = dom((elementary_tree 1) --> [1,0]) with-replacement (<*0*>,dom A) by TREES_2:def 12; reconsider d = <*0*> as Element of elementary_tree 1 by TREES_1:55; A3:dom x = elementary_tree 1 with-replacement (d,dom A) by A2,FUNCOP_1:19; @((elementary_tree 1) --> [1,0],<*0*>, A) = x by A1,Def8; then reconsider x as finite DecoratedTree of [: NAT,NAT :] by A3,Lm2; A4: dom x = dom((elementary_tree 1) --> [1,0]) with-replacement (<*0*>,dom A) by A1,TREES_2:def 12; for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) proof let v be Element of dom x; set e = (elementary_tree 1) --> [1,0]; now per cases by A1,A4,TREES_2:def 12; suppose A5: not <*0*> is_a_prefix_of v & x .v = e.v; then A6: not ex s st s in dom A & v = <*0*>^s by TREES_1:8; then A7: v in dom e & not <*0*> is_a_proper_prefix_of v by A1,A4,TREES_1:def 12; reconsider v'=v as Element of dom e by A1,A4,A6,TREES_1:def 12; A8: dom e = {{},<*0*>} by Th9,FUNCOP_1:19; then A9: v = {} by A5,A7,TARSKI:def 2; A10: succ v' = {<*0*>} proof now let x; thus x in succ v' implies x in {<*0*>} proof assume x in succ v'; then x in { v'^<*n*> : v'^<*n*> in dom e } by TREES_2:def 5; then consider n such that A11: x = v'^<*n*> & v'^<*n*> in dom e; A12: x = <*n*> & <*n*> in dom e by A9,A11,FINSEQ_1:47; then <*n*> = {} or <*n*> = <*0*> by A8,TARSKI:def 2; hence thesis by A12,TARSKI:def 1,TREES_1:4; end; assume x in {<*0*>}; then A13: x = <*0*> by TARSKI:def 1; then A14: x = v'^<*0*> by A9,FINSEQ_1:47; then v'^<*0*> in dom e by A8,A13,TARSKI:def 2; then x in { v'^<*n*> : v'^<*n*> in dom e } by A14; hence x in succ v' by TREES_2:def 5; end; hence thesis by TARSKI:2; end; {} is_a_proper_prefix_of <*0*> by Lm1; then succ v= succ v' by A1,A4,A9,Th17; then 1 = card succ v by A10,CARD_1:79; then A15: branchdeg v = 1 by PRELAMB:def 4; hence branchdeg v <= 2; x .v = [1,0] proof v in elementary_tree 1 by A7,FUNCOP_1:19; hence thesis by A5,FUNCOP_1:13; end; hence thesis by A15; suppose ex s st s in dom A & v = <*0*>^s & x .v = A.s; then consider s such that A16: s in dom A & v = <*0*>^s & x .v = A.s; reconsider s as Element of dom A by A16; A17: branchdeg s <= 2 & (branchdeg s = 0 implies A .s = [0,0] or ex m st A .s = [3,m]) & (branchdeg s = 1 implies A .s = [1,0] or A .s = [1,1]) & (branchdeg s = 2 implies A .s = [2,0]) by Def6; succ v,succ s are_equipotent by A1,A4,A16,Th19; then card succ v = card succ s by CARD_1:81; then A18: branchdeg v = card succ s by PRELAMB:def 4; hence branchdeg v <= 2 by A17,PRELAMB:def 4; thus thesis by A16,A17,A18,PRELAMB:def 4; end; hence thesis; end; hence thesis by Def6; end; theorem Th33: ((elementary_tree 1)-->[1,1]) with-replacement (<*0*>,A) is MP-wff proof set x = ((elementary_tree 1) --> [1,1]) with-replacement (<*0*> , A); A1: <*0*> in dom ((elementary_tree 1) --> [1,1]) proof <*0*> in elementary_tree 1 by TREES_1:55; hence thesis by FUNCOP_1:19; end; then A2: dom x = dom((elementary_tree 1) --> [1,1]) with-replacement (<*0*>,dom A) by TREES_2:def 12; reconsider d = <*0*> as Element of elementary_tree 1 by TREES_1:55; A3: dom x = elementary_tree 1 with-replacement (d,dom A) by A2,FUNCOP_1:19; @((elementary_tree 1) --> [1,1], <*0*> , A) = ((elementary_tree 1) --> [1,1]) with-replacement (<*0*> , A) by A1,Def8; then reconsider x = ((elementary_tree 1) --> [1,1]) with-replacement (<*0*> , A) as finite DecoratedTree of [: NAT,NAT :] by A3,Lm2; A4: dom x = dom((elementary_tree 1) --> [1,1]) with-replacement (<*0*>,dom A) by A1,TREES_2:def 12; for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) proof let v be Element of dom x; set e = (elementary_tree 1) --> [1,1]; now per cases by A1,A4,TREES_2:def 12; suppose A5: not <*0*> is_a_prefix_of v & x .v = e.v; then A6: not ex s st s in dom A & v = <*0*>^s by TREES_1:8; then A7: v in dom e & not <*0*> is_a_proper_prefix_of v by A1,A4,TREES_1:def 12; reconsider v'=v as Element of dom e by A1,A4,A6,TREES_1:def 12; A8: dom e = {{},<*0*>} by Th9,FUNCOP_1:19; then A9: v = {} by A5,A7,TARSKI:def 2; A10: succ v' = {<*0*>} proof now let x; thus x in succ v' implies x in {<*0*>} proof assume x in succ v'; then x in { v'^<*n*> : v'^<*n*> in dom e } by TREES_2:def 5; then consider n such that A11: x = v'^<*n*> & v'^<*n*> in dom e; A12: x = <*n*> & <*n*> in dom e by A9,A11,FINSEQ_1:47; then <*n*> = {} or <*n*> = <*0*> by A8,TARSKI:def 2; hence thesis by A12,TARSKI:def 1,TREES_1:4; end; assume x in {<*0*>}; then A13: x = <*0*> by TARSKI:def 1; then A14: x = v'^<*0*> by A9,FINSEQ_1:47; then v'^<*0*> in dom e by A8,A13,TARSKI:def 2; then x in { v'^<*n*> : v'^<*n*> in dom e } by A14; hence x in succ v' by TREES_2:def 5; end; hence thesis by TARSKI:2; end; {} is_a_proper_prefix_of <*0*> by Lm1; then succ v= succ v' by A1,A4,A9,Th17; then 1 = card succ v by A10,CARD_1:79; then A15: branchdeg v = 1 by PRELAMB:def 4; hence branchdeg v <= 2; x .v = [1,1] proof v in elementary_tree 1 by A7,FUNCOP_1:19; hence thesis by A5,FUNCOP_1:13; end; hence thesis by A15; suppose ex s st s in dom A & v = <*0*>^s & x .v = A.s; then consider s such that A16: s in dom A & v = <*0*>^s & x .v = A.s; reconsider s as Element of dom A by A16; A17: branchdeg s <= 2 & (branchdeg s = 0 implies A .s = [0,0] or ex m st A .s = [3,m]) & (branchdeg s = 1 implies A .s = [1,0] or A .s = [1,1]) & (branchdeg s = 2 implies A .s = [2,0]) by Def6; succ v,succ s are_equipotent by A1,A4,A16,Th19; then card succ v = card succ s by CARD_1:81; then A18: branchdeg v = card succ s by PRELAMB:def 4; hence branchdeg v <= 2 by A17,PRELAMB:def 4; thus thesis by A16,A17,A18,PRELAMB:def 4; end; hence thesis; end; hence thesis by Def6; end; theorem Th34: ((((elementary_tree 2)-->[2,0]) with-replacement (<*0*>,A))) with-replacement (<*1*>,B) is MP-wff proof set y = ((elementary_tree 2)-->[2,0]) with-replacement (<*0*>,A); set x = y with-replacement (<*1*>,B); A1: <*0*> in dom((elementary_tree 2)-->[2,0]) proof <*0*> in elementary_tree 2 by TREES_1:55; hence thesis by FUNCOP_1:19; end; y is DecoratedTree of [: NAT,NAT :] proof @((elementary_tree 2) --> [2,0],<*0*>,A) = y by A1,Def8; hence thesis; end; then reconsider y as DecoratedTree of [: NAT,NAT :]; A2: dom y = dom((elementary_tree 2)-->[2,0]) with-replacement (<*0*>,dom A) by A1,TREES_2:def 12; A3: <*1*> in elementary_tree 2 by TREES_1:55; A4: dom ((elementary_tree 2) --> [2,0]) = elementary_tree 2 by FUNCOP_1:19; A5: <*1*> in dom((elementary_tree 2)-->[2,0]) by A3,FUNCOP_1:19; A6: not <*0*> is_a_proper_prefix_of <*1*> proof assume not thesis; then <*0*> is_a_prefix_of <*1*> by XBOOLE_0:def 8; hence contradiction by TREES_1:16; end; then A7: <*1*> in dom y by A1,A2,A5,TREES_1:def 12; reconsider da = dom A as finite Tree; reconsider d =<*0*> as Element of elementary_tree 2 by A1,FUNCOP_1:19; dom y = (elementary_tree 2) with-replacement(d,da) by A4,TREES_2:def 12; then reconsider dy = dom y as finite Tree; reconsider d1 = <*1*> as Element of dy by A1,A2,A5,A6,TREES_1:def 12; reconsider db = dom B as finite Tree; A8: dom x = dy with-replacement (d1,db) by TREES_2:def 12; @(y,<*1*>,B) = x by A7,Def8; then reconsider x as finite DecoratedTree of [: NAT,NAT :] by A8,Lm2; A9: dom x = dom y with-replacement (<*1*>,dom B) by A7,TREES_2:def 12; for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) proof let v be Element of dom x; set e = (elementary_tree 2)-->[2,0]; now per cases by A7,A9,TREES_2:def 12; suppose A10: not <*1*> is_a_prefix_of v & x .v = y .v; then A11: not ex s st s in dom B & v = <*1*>^s by TREES_1:8; then A12: v in dom e with-replacement (<*0*>,dom A) by A2,A7,A9,TREES_1:def 12; now per cases by A1,A12,TREES_2:def 12; suppose A13: not <*0*> is_a_prefix_of v & y.v = e.v; then A14: not ex s st s in dom A & v = <*0*>^s by TREES_1:8; then A15: v in dom e & not <*0*> is_a_proper_prefix_of v by A1,A12,TREES_1:def 12; reconsider v'=v as Element of dom e by A1,A12,A14,TREES_1:def 12; A16: dom e = {{},<*0*>,<*1*>} by Th10,FUNCOP_1:19; then A17: v = {} by A10,A13,A15,ENUMSET1:13; A18: succ v' = {<*0*>,<*1*>} proof now let x; thus x in succ v' implies x in {<*0*>,<*1*>} proof assume x in succ v'; then x in { v'^<*n*> : v'^<*n*> in dom e } by TREES_2:def 5; then consider n such that A19: x = v'^<*n*> & v'^<*n*> in dom e; A20: x = <*n*> & <*n*> in dom e by A17,A19,FINSEQ_1:47; then <*n*> = {} or <*n*> = <*0*> or <*n*> = <*1*> by A16,ENUMSET1:13; hence thesis by A20,TARSKI:def 2,TREES_1:4; end; assume x in {<*0*>,<*1*>}; then A21: x = <*0*> or x = <*1*> by TARSKI:def 2; now per cases by A17,A21,FINSEQ_1:47; suppose A22: x = v'^<*0*>; then v'^<*0*> in dom e by A16,A21,ENUMSET1:14; then x in { v'^<*n*> : v'^<*n*> in dom e } by A22; hence x in succ v' by TREES_2:def 5; suppose A23: x = v'^<*1*>; then v'^<*1*> in dom e by A16,A21,ENUMSET1:14; then x in { v'^<*n*> : v'^<*n*> in dom e } by A23; hence x in succ v' by TREES_2:def 5; end; hence x in succ v'; end; hence thesis by TARSKI:2; end; A24: {} is_a_proper_prefix_of <*0*> by Lm1; A25: {} is_a_proper_prefix_of <*1*> by Lm1; A26: succ v = succ v' proof reconsider v'' = v as Element of dom y by A7,A9,A11,TREES_1:def 12; succ v'' = succ v' by A1,A2,A17,A24,Th17; hence thesis by A7,A9,A17,A25,Th17; end; <*0*> <> <*1*> by TREES_1:16; then A27: 2 = card succ v by A18,A26,CARD_2:76; hence branchdeg v <= 2 by PRELAMB:def 4; x .v = [2,0] proof v in elementary_tree 2 by A15,FUNCOP_1:19; hence thesis by A10,A13,FUNCOP_1:13; end; hence thesis by A27,PRELAMB:def 4; suppose ex s st s in dom A & v = <*0*>^s & y.v = A.s; then consider s such that A28: s in dom A & v = <*0*>^s & y.v = A.s; reconsider s as Element of dom A by A28; A29: branchdeg s <= 2 & (branchdeg s = 0 implies A .s = [0,0] or ex m st A .s = [3,m]) & (branchdeg s = 1 implies A .s = [1,0] or A .s = [1,1]) & (branchdeg s = 2 implies A .s = [2,0]) by Def6; A30: not <*1*>,v are_c=-comparable by A28,Th3; succ v,succ s are_equipotent proof reconsider v'=v as Element of dom y by A7,A9,A11,TREES_1:def 12; succ v',succ s are_equipotent by A1,A2,A28,Th19; hence thesis by A7,A9,A30,Th18; end; then card succ v = card succ s by CARD_1:81; then A31: branchdeg v = card succ s by PRELAMB:def 4; hence branchdeg v <= 2 by A29,PRELAMB:def 4; thus thesis by A10,A28,A29,A31,PRELAMB:def 4; end; hence thesis; suppose ex s st s in dom B & v = <*1*>^s & x .v = B.s; then consider s such that A32: s in dom B & v = <*1*>^s & x .v = B.s; reconsider s as Element of dom B by A32; A33: branchdeg s <= 2 & (branchdeg s = 0 implies B .s = [0,0] or ex m st B .s = [3,m]) & (branchdeg s = 1 implies B .s = [1,0] or B .s = [1,1]) & (branchdeg s = 2 implies B .s = [2,0]) by Def6; succ v,succ s are_equipotent by A7,A9,A32,Th19; then card succ v = card succ s by CARD_1:81; then branchdeg v = card succ s by PRELAMB:def 4; hence thesis by A32,A33,PRELAMB:def 4; end; hence thesis; end; hence thesis by Def6; end; definition let A; func 'not' A -> MP-wff equals :Def9: ((elementary_tree 1)-->[1,0]) with-replacement (<*0*>,A); coherence by Th32; func (#) A -> MP-wff equals :Def10: ((elementary_tree 1)-->[1,1]) with-replacement (<*0*>,A); coherence by Th33; let B; func A '&' B -> MP-wff equals :Def11: ((((elementary_tree 2)-->[2,0]) with-replacement (<*0*>,A))) with-replacement (<*1*>,B); coherence by Th34; end; definition let A; func ? A -> MP-wff equals 'not' (#) 'not' A; correctness; let B; func A 'or' B -> MP-wff equals 'not'('not' A '&' 'not' B); correctness; func A => B -> MP-wff equals 'not'(A '&' 'not' B); correctness; end; theorem Th35: (elementary_tree 0) --> [3,n] is MP-wff proof set x = (elementary_tree 0) --> [3,n]; A1: dom x = { {} } by FUNCOP_1:19,TREES_1:56; then reconsider x as finite DecoratedTree of [: NAT,NAT :] by Lm2; A2: dom x = elementary_tree 0 by FUNCOP_1:19; for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) proof let v be Element of dom x; A3: v = {} by A2,TARSKI:def 1,TREES_1:56; A4: succ v = {} proof assume A5: not thesis; consider y being Element of succ v; y in succ v by A5; then y in { v^<*m*> : v^<*m*> in dom x } by TREES_2:def 5; then consider m such that A6: y = v^<*m*> & v^<*m*> in dom x; y = <*m*> & <*m*> in dom x by A3,A6,FINSEQ_1:47; then <*m*> = {} by A1,TARSKI:def 1; hence contradiction by TREES_1:4; end; then 0 = branchdeg v by CARD_1:78,PRELAMB:def 4; hence branchdeg v <= 2; thus branchdeg v = 0 implies x .v = [0,0] or ex m st x .v =[3,m] proof assume branchdeg v = 0; x .v = [3,n] by A2,FUNCOP_1:13; hence thesis; end; thus thesis by A4,CARD_1:78,PRELAMB:def 4; end; hence thesis by Def6; end; theorem Th36: (elementary_tree 0) --> [0,0] is MP-wff proof set x = (elementary_tree 0) --> [0,0]; dom x = { {} } by FUNCOP_1:19,TREES_1:56; then reconsider x as finite DecoratedTree of [: NAT,NAT :] by Lm2; A1: dom x = elementary_tree 0 by FUNCOP_1:19; A2: dom x = { {} } by FUNCOP_1:19,TREES_1:56; for v being Element of dom x holds branchdeg v <= 2 & (branchdeg v = 0 implies x .v = [0,0] or ex k st x .v = [3,k]) & (branchdeg v = 1 implies x .v = [1,0] or x .v = [1,1]) & (branchdeg v = 2 implies x .v = [2,0]) proof let v be Element of dom x; A3: v = {} by A1,TARSKI:def 1,TREES_1:56; A4: succ v = {} proof assume A5: not thesis; consider y being Element of succ v; y in succ v by A5; then y in { v^<*m*> : v^<*m*> in dom x } by TREES_2:def 5; then consider m such that A6: y = v^<*m*> & v^<*m*> in dom x; y = <*m*> & <*m*> in dom x by A3,A6,FINSEQ_1:47; then <*m*> = {} by A2,TARSKI:def 1; hence contradiction by TREES_1:4; end; then 0 = branchdeg v by CARD_1:78,PRELAMB:def 4; hence branchdeg v <= 2; thus thesis by A1,A4,CARD_1:78,FUNCOP_1:13,PRELAMB:def 4; end; hence thesis by Def6; end; definition let p; func @p -> MP-wff equals :Def15: (elementary_tree 0) --> p; coherence proof consider x1,x2 such that A1: x1 in {3} & x2 in NAT & p = [x1,x2] by Def3,ZFMISC_1:def 2; x1 = 3 by A1,TARSKI:def 1; hence (elementary_tree 0) --> p is MP-wff by A1,Th35; end; end; theorem Th37: @p = @q implies p = q proof A1: {} in elementary_tree 0 by TREES_1:47; assume A2: @p = @q; A3: @p = (elementary_tree 0) --> p by Def15; A4: @q = (elementary_tree 0) --> q by Def15; p = @p.{} by A1,A3,FUNCOP_1:13 .= q by A1,A2,A4,FUNCOP_1:13; hence thesis; end; Lm3: <*0*> in dom ((elementary_tree 1)-->[n,m]) proof <*0*> in elementary_tree 1 by Th9,TARSKI:def 2; hence thesis by FUNCOP_1:19; end; theorem Th38: 'not' A = 'not' B implies A = B proof assume A1: 'not' A = 'not' B; A2: <*0*> in dom((elementary_tree 1)-->[1,0]) by Lm3; ((elementary_tree 1)-->[1,0]) with-replacement (<*0*>,A) = 'not' A by Def9 .= ((elementary_tree 1)-->[1,0]) with-replacement (<*0*>,B) by A1,Def9; hence thesis by A2,Th16; end; theorem Th39: (#)A = (#)B implies A = B proof set AA = (elementary_tree 1)-->[1,1]; assume A1: (#)A = (#)B; A2: <*0*> in dom AA by Lm3; AA with-replacement (<*0*>,A) = (#)A by Def10 .= AA with-replacement(<*0*>,B) by A1,Def10; hence thesis by A2,Th16; end; theorem Th40: (A '&' B) = (A1 '&' B1) implies A = A1 & B = B1 proof set e = elementary_tree 2; set y = (e-->[2,0]) with-replacement (<*0*>,A); set y1 = (e-->[2,0]) with-replacement (<*0*>,A1); A1: A '&' B = y with-replacement (<*1*>,B) by Def11; A2: A1 '&' B1 = y1 with-replacement (<*1*>,B1) by Def11; assume A3: A '&' B = A1 '&' B1; A4: not <*0*>,<*1*> are_c=-comparable by TREES_1:23; A5: not <*1*> is_a_proper_prefix_of <*0*> by Th7; A6: <*0*> in e & <*1*> in e by TREES_1:55; A7: dom (e --> [2,0]) = e by FUNCOP_1:19; then A8: <*0*> in dom(e-->[2,0]) with-replacement (<*1*>,dom B) by A5,A6,TREES_1:def 12; A9: dom y = dom(e-->[2,0]) with-replacement (<*0*>,dom A) & dom y1 = dom(e-->[2,0]) with-replacement (<*0*>,dom A1) by A6,A7,TREES_2:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A10: <*1*> in dom y & <*1*> in dom y1 by A6,A7,A9,TREES_1:def 12; then A11: dom (A '&' B) = dom y with-replacement (<*1*>,dom B) & dom (A1 '&' B1) = dom y1 with-replacement (<*1*>,dom B1) by A1,A2,TREES_2:def 12; now let s; thus s in dom B implies s in dom B1 proof assume s in dom B; then A12: <*1*>^s in dom(A1 '&' B1) by A3,A10,A11,TREES_1:def 12; now per cases; suppose s = {}; hence thesis by TREES_1:47; suppose s <> {}; then <*1*> is_a_proper_prefix_of <*1*>^s by TREES_1:33; then ex w st w in dom B1 & <*1*>^s = <*1*>^w by A10,A11,A12,TREES_1:def 12; hence thesis by FINSEQ_1:46; end; hence thesis; end; assume s in dom B1; then A13: <*1*>^s in dom(A '&' B) by A3,A10,A11,TREES_1:def 12; now per cases; suppose s = {}; hence s in dom B by TREES_1:47; suppose s <> {}; then <*1*> is_a_proper_prefix_of <*1*>^s by TREES_1:33; then ex w st w in dom B & <*1*>^s = <*1*>^w by A10,A11,A13,TREES_1: def 12; hence s in dom B by FINSEQ_1:46; end; hence s in dom B; end; then A14: dom B = dom B1 by TREES_2:def 1; A15: dom (A '&' B) = (dom(e-->[2,0]) with-replacement (<*1*>,dom B)) with-replacement (<*0*>,dom A) by A4,A6,A7,A9,A11,TREES_2:10; dom (A1 '&' B1) = (dom(e-->[2,0]) with-replacement (<*1*>,dom B)) with-replacement (<*0*>,dom A1) by A4,A6,A7,A9,A11,A14,TREES_2:10; then A16: dom A = dom A1 by A3,A8,A15,Th15; A17: for s st s in dom B holds B.s = B1.s proof let s; assume s in dom B; then A18: <*1*>^s in dom(A1 '&' B1) by A3,A10,A11,TREES_1:def 12; A19: <*1*> is_a_prefix_of <*1*>^s by TREES_1:8; then consider w such that A20: w in dom B1 & <*1*>^s = <*1*>^w & (A1 '&' B1).(<*1*>^s) = B1.w by A2,A10,A11,A18,TREES_2:def 12; A21: s = w by A20,FINSEQ_1:46; ex u st u in dom B & <*1*>^s = <*1*>^u & (A '&' B).(<*1*>^s) = B.u by A1,A3,A10,A11,A18,A19,TREES_2:def 12; hence thesis by A3,A20,A21,FINSEQ_1:46; end; then A22: B = B1 by A14,TREES_2:33; for s st s in dom A holds A.s = A1.s proof let s; assume A23: s in dom A; then A24: <*0*>^s in dom y by A6,A7,A9,TREES_1:def 12; not <*1*> is_a_proper_prefix_of <*0*>^s by Th5; then A25: <*0*>^s in dom (A '&' B) by A10,A11,A24,TREES_1:def 12; now given w such that A26: w in dom B & <*0*>^s = <*1*>^w & (A '&' B).(<*0*>^s) = B.w; <*0*> is_a_prefix_of <*1*>^w by A26,TREES_1:8; hence contradiction by Th6; end; then A27: not <*1*> is_a_prefix_of <*0*>^s & (A '&' B).(<*0*>^s) = y.(<*0*> ^s) by A1,A10,A11,A25,TREES_2:def 12; A28: <*0*> is_a_prefix_of <*0*>^s by TREES_1:8; then ex w st w in dom A & <*0*>^s = <*0*>^w & y.(<*0*>^s) = A.w by A6,A7,A9,A24,TREES_2:def 12; then A29: A.s = (A1 '&' B).(<*0*>^s) by A3,A22,A27,FINSEQ_1:46; A30: <*0*>^s in dom y1 by A6,A7,A9,A16,A23,TREES_1:def 12; now given w such that A31: w in dom B1 & <*0*>^s = <*1*>^w & (A1 '&' B1).(<*0*>^s) = B1.w; <*0*> is_a_prefix_of <*1*>^w by A31,TREES_1:8; hence contradiction by Th6; end; then A32: not <*1*> is_a_prefix_of <*0*>^s & (A1 '&' B1).(<*0*>^s) = y1.(<* 0*>^s) by A2,A3,A10,A11,A25,TREES_2:def 12; ex u st u in dom A1 & <*0*>^s = <*0*>^u & y1.(<*0*>^s) = A1.u by A6,A7,A9,A28,A30,TREES_2:def 12; hence thesis by A22,A29,A32,FINSEQ_1:46; end; hence thesis by A14,A16,A17,TREES_2:33; end; definition func VERUM -> MP-wff equals :Def16: (elementary_tree 0) --> [0,0]; coherence by Th36; end; canceled; theorem Th42: card dom A = 1 implies A = VERUM or ex p st A = @p proof assume A1: card dom A = 1; A2: {} in dom A by TREES_1:47; consider x such that A3: dom A = {x} by A1,CARD_2:60; A4: x = {} by A2,A3,TARSKI:def 1; A5: dom A = {{}} by A2,A3,TARSKI:def 1; A6: dom A = elementary_tree 0 by A2,A3,TARSKI:def 1,TREES_1:56; reconsider x as Element of dom A by A3,TARSKI:def 1; succ x = {} proof A7: succ x = { x^<*n*>: x^<*n*> in dom A } by TREES_2:def 5; assume A8: not thesis; consider y being Element of succ x; y in succ x by A8; then consider n such that A9: y = x^<*n*> & x^<*n*> in dom A by A7; A10: y = {} by A5,A9,TARSKI:def 1; y = <*n*> by A4,A9,FINSEQ_1:47; hence contradiction by A10,TREES_1:4; end; then A11: branchdeg x = 0 by CARD_1:78,PRELAMB:def 4; now per cases by A11,Def6; suppose A.x = [0,0]; then for z holds z in dom A implies A.z = [0,0] by A3,TARSKI:def 1; hence thesis by A6,Def16,FUNCOP_1:17; suppose ex n st A.x = [3,n]; then consider n such that A12: A.x = [3,n]; for z holds z in dom A implies A.z = [3,n] by A3,A12,TARSKI:def 1; then A13: A = (elementary_tree 0) --> [3,n] by A6,FUNCOP_1:17; reconsider p = [3,n] as MP-variable by Def3,ZFMISC_1:128; A = @p by A13,Def15; hence thesis; end; hence thesis; end; theorem Th43: card dom A >= 2 implies (ex B st A = 'not' B or A = (#)B) or ex B,C st A = B '&' C proof assume A1: card dom A >= 2; set b = branchdeg (Root dom A); set a = Root dom A; A2: b <= 2 by Def6; A3: now assume b = 0; then card dom A = 1 by Th22; hence contradiction by A1; end; now per cases by A2,A3,CQC_THE1:3; case A4: b = 1; then card succ a = 1 by PRELAMB:def 4; then consider x such that A5: succ a = {x} by CARD_2:60; x in succ a by A5,TARSKI:def 1; then reconsider x' = x as Element of dom A; take B = A|x'; now per cases by A4,Def6; suppose A.a = [1,0]; then Root A = [1,0] by Def2; then A = (((elementary_tree 1) --> [1,0]) with-replacement (<*0*>,B)) by A5,Th28 .= 'not' B by Def9; hence A = 'not' B or A = (#) B; suppose A.a = [1,1]; then Root A = [1,1] by Def2; then A = (((elementary_tree 1) --> [1,1]) with-replacement (<*0*>,B)) by A5,Th28 .= (#) B by Def10; hence A = 'not' B or A = (#) B; end; hence thesis; case A6: b = 2; then A.a = [2,0] by Def6; then A7: Root A = [2,0] by Def2; A8: succ a = { <*0*>,<*1*> } by A6,Th24; then <*0*> in succ a & <*1*> in succ a by TARSKI:def 2; then reconsider x = <*0*>, y = <*1*> as Element of dom A; take B = A|x; take C = A|y; A = ((elementary_tree 2) --> [2,0]) with-replacement (<*0*>,A|x) with-replacement (<*1*>,A|y) by A7,A8,Th30 .= B '&' C by Def11; hence thesis; end; hence thesis; end; theorem Th44: card dom A < card dom 'not' A proof set e = elementary_tree 1; <*0*> in e by Th9,TARSKI:def 2; then A1: <*0*> in dom (e --> [1,0]) by FUNCOP_1:19; 'not' A = (e --> [1,0]) with-replacement (<*0*>,A) by Def9; then A2: dom 'not' A = dom (e --> [1,0]) with-replacement (<*0*>, dom A) by A1,TREES_2:def 12; then reconsider o = <*0*> as Element of dom 'not' A by A1,TREES_1:def 12; A3: dom A = (dom 'not' A)|o proof now let s; thus s in dom A implies o^s in dom 'not' A by A1,A2,TREES_1:def 12; assume A4: o^s in dom 'not' A; now per cases; suppose s = {}; hence s in dom A by TREES_1:47; suppose s <> {}; then o is_a_proper_prefix_of o^s by TREES_1:33; then ex w st w in dom A & o^s = o^w by A1,A2,A4,TREES_1:def 12; hence s in dom A by FINSEQ_1:46; end; hence s in dom A; end; hence thesis by TREES_1:def 9; end; Root (dom 'not' A) = {} by Def1; then o <> Root (dom 'not' A) by TREES_1:4; hence thesis by A3,Th26; end; theorem Th45: card dom A < card dom (#)A proof set e = elementary_tree 1; <*0*> in e by Th9,TARSKI:def 2; then A1: <*0*> in dom (e --> [1,1]) by FUNCOP_1:19; (#)A = (e --> [1,1]) with-replacement (<*0*>,A) by Def10; then A2: dom (#)A = dom (e --> [1,1]) with-replacement (<*0*>, dom A) by A1,TREES_2:def 12; then reconsider o = <*0*> as Element of dom (#)A by A1,TREES_1:def 12; A3: dom A = (dom (#)A)|o proof now let s; thus s in dom A implies o^s in dom (#)A by A1,A2,TREES_1:def 12; assume A4: o^s in dom (#)A; now per cases; suppose s = {}; hence s in dom A by TREES_1:47; suppose s <> {}; then o is_a_proper_prefix_of o^s by TREES_1:33; then ex w st w in dom A & o^s = o^w by A1,A2,A4,TREES_1:def 12; hence s in dom A by FINSEQ_1:46; end; hence s in dom A; end; hence thesis by TREES_1:def 9; end; Root (dom (#)A) = {} by Def1; then o <> Root (dom (#)A) by TREES_1:4; hence thesis by A3,Th26; end; theorem Th46: card dom A < card dom A '&' B & card dom B < card dom A '&' B proof set e = elementary_tree 2; set y = (e-->[2,0]) with-replacement(<*0*>,A); A1: A '&' B = y with-replacement (<*1*>,B) by Def11; A2: <*0*> in e & <*1*> in e by TREES_1:55; A3: dom (e --> [2,0]) = e by FUNCOP_1:19; then A4: dom y = dom(e-->[2,0]) with-replacement (<*0*>,dom A) by A2,TREES_2:def 12; then A5: <*0*> in dom y by A2,A3,TREES_1:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A6: <*1*> in dom y by A2,A3,A4,TREES_1:def 12; then A7: dom (A '&' B) = dom y with-replacement (<*1*>,dom B) by A1,TREES_2:def 12; not <*1*> is_a_proper_prefix_of <*0*> by Th7; then reconsider o = <*0*> as Element of dom A '&' B by A5,A6,A7,TREES_1:def 12; A8: dom A = (dom A '&' B)|o proof now let s; thus s in dom A implies o^s in dom A '&' B proof assume s in dom A; then A9: o^s in dom y by A2,A3,A4,TREES_1:def 12; not <*1*> is_a_proper_prefix_of o^s by Th5; hence o^s in dom A '&' B by A6,A7,A9,TREES_1:def 12; end; assume A10: o^s in dom A '&' B; now per cases; suppose s = {}; hence s in dom A by TREES_1:47; suppose A11: s <> {}; now given w such that A12: w in dom B & o^s = <*1*>^w; o is_a_prefix_of <*1*>^w by A12,TREES_1:8; hence contradiction by Th6; end; then A13: o^s in dom y & not <*1*> is_a_proper_prefix_of o^s by A6,A7,A10,TREES_1:def 12; o is_a_proper_prefix_of o^s by A11,TREES_1:33; then ex w st w in dom A & o^s = o^w by A2,A3,A4,A13,TREES_1:def 12; hence s in dom A by FINSEQ_1:46; end; hence s in dom A; end; hence thesis by TREES_1:def 9; end; A14: Root (dom A '&' B) = {} by Def1; then o <> Root (dom A '&' B) by TREES_1:4; hence card dom A < card dom A '&' B by A8,Th26; reconsider u = <*1*> as Element of dom A '&' B by A6,A7,TREES_1:def 12; A15: dom B = (dom A '&' B)|u proof now let s; thus s in dom B implies u^s in dom A '&' B by A6,A7,TREES_1:def 12; assume A16: u^s in dom A '&' B; now per cases; suppose s = {}; hence s in dom B by TREES_1:47; suppose s <> {}; then <*1*> is_a_proper_prefix_of u^s by TREES_1:33; then ex w st w in dom B & u^s = <*1*>^w by A6,A7,A16,TREES_1:def 12 ; hence s in dom B by FINSEQ_1:46; end; hence s in dom B; end; hence thesis by TREES_1:def 9; end; u <> Root (dom A '&' B) by A14,TREES_1:4; hence thesis by A15,Th26; end; definition let IT be MP-wff; attr IT is atomic means :Def17: ex p st IT = @p; attr IT is negative means :Def18: ex A st IT = 'not' A; attr IT is necessitive means :Def19: ex A st IT = (#) A; attr IT is conjunctive means :Def20: ex A,B st IT = A '&' B; end; definition cluster atomic MP-wff; existence proof reconsider p = [3,0] as MP-variable by Def3,ZFMISC_1:128; take @p; take p; thus thesis; end; cluster negative MP-wff; existence proof set A = VERUM; take 'not' A; take A; thus thesis; end; cluster necessitive MP-wff; existence proof set A = VERUM; take (#)A; take A; thus thesis; end; cluster conjunctive MP-wff; existence proof set A = VERUM; set B = VERUM; take A '&' B; take B; take A; thus thesis; end; end; scheme MP_Ind { Prop[Element of MP-WFF] }: for A being Element of MP-WFF holds Prop[A] provided A1: Prop[VERUM] and A2: for p being MP-variable holds Prop[@p] and A3: for A being Element of MP-WFF st Prop[A] holds Prop['not' A] and A4: for A being Element of MP-WFF st Prop[A] holds Prop[(#) A] and A5: for A, B being Element of MP-WFF st Prop[A] & Prop[B] holds Prop[A '&' B] proof defpred P[Nat] means for A st card dom A <= $1 holds Prop[A]; A6: P[0] proof let A such that A7: card dom A <= 0; card dom A = 0 by A7,NAT_1:18; hence thesis by CARD_2:59; end; A8: for k st P[k] holds P[k+1] proof let k such that A9: for A st card dom A <= k holds Prop[A]; let A such that A10: card dom A <= k + 1; set a = Root dom A; set b = branchdeg a; A11: b <= 2 by Def6; now per cases by A11,CQC_THE1:3; suppose b = 0; then A12: card dom A = 1 by Th22; now per cases by A12,Th42; suppose A = VERUM; hence Prop[A] by A1; suppose ex p st A = @p; hence Prop[A] by A2; end; hence Prop[A]; suppose A13: b = 1; then A14: succ a ={<*0*>} by Th23; then <*0*> in succ a by TARSKI:def 1; then reconsider o = <*0*> as Element of dom A; A15: A = ((elementary_tree 1) --> Root A) with-replacement (<*0*>, A|o) by A14,Th28; A16: Root A = A.a by Def2; now per cases by A13,Def6; suppose A.a = [1,0]; then A17: A = 'not'(A|o) by A15,A16,Def9; A18: dom (A|o) = (dom A)|o by TREES_2:def 11; o <> {} by TREES_1:4; then o <> Root dom A by Def1; then card ((dom A)|o) < card dom A by Th26; then card dom (A|o) < k + 1 by A10,A18,AXIOMS:22; then card dom (A|o) <= k by NAT_1:38; then Prop[A|o] by A9; hence Prop[A] by A3,A17; suppose A.a = [1,1]; then A19: A = (#)(A|o) by A15,A16,Def10; A20: dom (A|o) = (dom A)|o by TREES_2:def 11; o <> {} by TREES_1:4; then o <> Root dom A by Def1; then card ((dom A)|o) < card dom A by Th26; then card dom (A|o) < k + 1 by A10,A20,AXIOMS:22; then card dom (A|o) <= k by NAT_1:38; then Prop[A|o] by A9; hence Prop[A] by A4,A19; end; hence thesis; suppose A21: b = 2; then A22: succ a ={<*0*>,<*1*>} by Th24; then <*0*> in succ a & <*1*> in succ a by TARSKI:def 2; then reconsider o1 = <*0*>, o2 = <*1*> as Element of dom A; A23: A = ((elementary_tree 2) --> Root A) with-replacement (<*0*>, A|o1) with-replacement (<*1*>,A|o2) by A22,Th30; Root A = A.a by Def2 .= [2,0] by A21,Def6; then A24: A = (A|o1) '&' (A|o2) by A23,Def11; A25: dom (A|o1) = (dom A)|o1 by TREES_2:def 11; o1 <> {} by TREES_1:4; then o1 <> Root dom A by Def1; then card ((dom A)|o1) < card dom A by Th26; then card dom (A|o1) < k + 1 by A10,A25,AXIOMS:22; then card dom (A|o1) <= k by NAT_1:38; then A26: Prop[A|o1] by A9; A27: dom (A|o2) = (dom A)|o2 by TREES_2:def 11; o2 <> {} by TREES_1:4; then o2 <> Root dom A by Def1; then card ((dom A)|o2) < card dom A by Th26; then card dom (A|o2) < k + 1 by A10,A27,AXIOMS:22; then card dom (A|o2) <= k by NAT_1:38; then Prop[A|o2] by A9; hence thesis by A5,A24,A26; end; hence thesis; end; A28: for n holds P[n] from Ind(A6,A8); let A; card dom A <= card dom A; hence Prop[A] by A28; end; theorem for A being Element of MP-WFF holds A = VERUM or A is atomic MP-wff or A is negative MP-wff or A is necessitive MP-wff or A is conjunctive MP-wff proof defpred Prop[Element of MP-WFF] means $1 = VERUM or $1 is atomic MP-wff or $1 is negative MP-wff or $1 is necessitive MP-wff or $1 is conjunctive MP-wff; A1: Prop[VERUM]; A2: for p being MP-variable holds Prop[@p] by Def17; A3: for A being Element of MP-WFF st Prop[A] holds Prop['not' A] by Def18; A4: for A being Element of MP-WFF st Prop[A] holds Prop[(#) A] by Def19; A5: for A,B being Element of MP-WFF st Prop[A] & Prop[B] holds Prop[A '&' B] by Def20; thus for A be Element of MP-WFF holds Prop[A] from MP_Ind(A1,A2,A3,A4,A5); end; theorem Th48: A = VERUM or (ex p st A = @p) or (ex B st A = 'not' B) or (ex B st A = (#) B) or (ex B,C st A = B '&' C) proof A1: card dom A = 0 or card dom A = 1 or card dom A >= 2 by CQC_THE1:3; now per cases by A1,CARD_2:59; suppose card dom A = 1; hence thesis by Th42; suppose card dom A >= 2; hence thesis by Th43; end; hence thesis; end; theorem Th49: @p <> 'not' A & @p <> (#)A & @p <> A '&' B proof set e0 = elementary_tree 0; set e1 = elementary_tree 1; set e2 = elementary_tree 2; @p = e0 --> p by Def15; then A1: dom @p = e0 by FUNCOP_1:19; A2: <*0*> in e1 by Th9,TARSKI:def 2; A3: dom (e1 --> [1,0]) = e1 & dom (e1 --> [1,1]) = e1 by FUNCOP_1:19; 'not' A = (e1 --> [1,0]) with-replacement (<*0*>,A) by Def9; then dom ('not' A) = e1 with-replacement (<*0*>,dom A) by A2,A3,TREES_2:def 12; then A4: <*0*> in dom ('not' A) by A2,TREES_1:def 12; thus @p <> 'not' A proof assume not thesis; then <*0*> = {} by A1,A4,TARSKI:def 1,TREES_1:56; hence contradiction by TREES_1:4; end; (#)A = (e1 --> [1,1]) with-replacement (<*0*>,A) by Def10; then dom ((#)A) = e1 with-replacement (<*0*>,dom A) by A2,A3,TREES_2:def 12; then A5: <*0*> in dom ((#)A) by A2,TREES_1:def 12; thus @p <> (#)A proof assume not thesis; then <*0*> = {} by A1,A5,TARSKI:def 1,TREES_1:56; hence contradiction by TREES_1:4; end; set y = (e2-->[2,0]) with-replacement (<*0*>,A); A6: A '&' B = y with-replacement (<*1*>,B) by Def11; A7: <*0*> in e2 & <*1*> in e2 by TREES_1:55; A8: dom (e2 --> [2,0]) = e2 by FUNCOP_1:19; then A9: dom y = dom(e2-->[2,0]) with-replacement (<*0*>,dom A) by A7,TREES_2:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A10: <*1*> in dom y by A7,A8,A9,TREES_1:def 12; then dom (A '&' B) = dom y with-replacement (<*1*>,dom B) by A6,TREES_2:def 12; then A11: <*1*> in dom (A '&' B) by A10,TREES_1:def 12; thus @p <> A '&' B proof assume not thesis; then <*1*> = {} by A1,A11,TARSKI:def 1,TREES_1:56; hence contradiction by TREES_1:4; end; end; theorem Th50: 'not' A <> (#)B & 'not' A <> B '&' C proof set e1 = elementary_tree 1; set e2 = elementary_tree 2; set E = e1 --> [1,0]; set F = e1 --> [1,1]; A1: <*0*> in e1 by Th9,TARSKI:def 2; A2: dom E = e1 & dom F = e1 by FUNCOP_1:19; A3: <*0*> in dom E & <*0*> in dom F by A1,FUNCOP_1:19; A4: 'not' A = E with-replacement (<*0*>,A) by Def9; A5: (#)B = F with-replacement (<*0*>,B) by Def10; A6: dom 'not' A = dom E with-replacement (<*0*>,dom A) by A3,A4,TREES_2:def 12; A7: dom (#)B = dom F with-replacement (<*0*>,dom B) by A3,A5,TREES_2:def 12; A8: {} in dom 'not' A & {} in dom (#)B by TREES_1:47; reconsider e = {} as Element of dom 'not' A by TREES_1:47; A9: now given u such that A10: u in dom A & e = <*0*>^u & 'not' A.e = A.u; <*0*> = e by A10,FINSEQ_1:48; hence contradiction by TREES_1:4; end; A11: e in e1 by TREES_1:47; then A12: E.e = [1,0] by FUNCOP_1:13; now given u such that A13: u in dom B & e = <*0*>^u & ((#)B).e = B.u; <*0*> = e by A13,FINSEQ_1:48; hence contradiction by TREES_1:4; end; then A14: not <*0*> is_a_prefix_of e & ((#) B).e = F.e by A3,A5,A7,A8,TREES_2:def 12; F.e = [1,1] & [1,0] <> [1,1] by A11,FUNCOP_1:13,ZFMISC_1:33; hence 'not' A <> (#)B by A3,A4,A6,A9,A12,A14,TREES_2:def 12; set y = (e2-->[2,0]) with-replacement (<*0*>,B); A15: B '&' C = y with-replacement (<*1*>,C) by Def11; A16: <*0*> in e2 & <*1*> in e2 by TREES_1:55; A17: dom (e2 --> [2,0]) = e2 by FUNCOP_1:19; then A18: dom y = dom(e2-->[2,0]) with-replacement (<*0*>,dom B) by A16,TREES_2:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A19: <*1*> in dom y by A16,A17,A18,TREES_1:def 12; then dom (B '&' C) = dom y with-replacement (<*1*>,dom C) by A15,TREES_2:def 12; then A20: <*1*> in dom (B '&' C) by A19,TREES_1:def 12; A21: now assume <*1*> in dom E; then <*1*> = {} or <*1*> = <*0*> by A2,Th9,TARSKI:def 2; hence contradiction by TREES_1:4,16; end; assume not thesis; then ex s st s in dom A & <*1*> = <*0*>^s by A3,A6,A20,A21,TREES_1:def 12; then <*0*> is_a_prefix_of <*1*> by TREES_1:8; hence contradiction by TREES_1: 16; end; theorem Th51: (#)A <> B '&' C proof set e1 = elementary_tree 1; set e2 = elementary_tree 2; set F = e1 --> [1,1]; A1: <*0*> in e1 by Th9,TARSKI:def 2; A2: dom F = e1 by FUNCOP_1:19; A3: <*0*> in dom F by A1,FUNCOP_1:19; (#)A = F with-replacement (<*0*>,A) by Def10; then A4: dom (#)A = dom F with-replacement (<*0*>,dom A) by A3,TREES_2:def 12; set y = (e2-->[2,0]) with-replacement (<*0*>,B); A5: B '&' C = y with-replacement (<*1*>,C) by Def11; A6: <*0*> in e2 & <*1*> in e2 by TREES_1:55; A7: dom (e2 --> [2,0]) = e2 by FUNCOP_1:19; then A8: dom y = dom(e2-->[2,0]) with-replacement (<*0*>,dom B) by A6,TREES_2:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A9: <*1*> in dom y by A6,A7,A8,TREES_1:def 12; then dom (B '&' C) = dom y with-replacement (<*1*>,dom C) by A5,TREES_2:def 12; then A10: <*1*> in dom (B '&' C) by A9,TREES_1:def 12; A11: now assume <*1*> in dom F; then <*1*> = {} or <*1*> = <*0*> by A2,Th9,TARSKI:def 2; hence contradiction by TREES_1:4,16; end; assume not thesis; then ex s st s in dom A & <*1*> = <*0*>^s by A3,A4,A10,A11,TREES_1:def 12; then <*0*> is_a_prefix_of <*1*> by TREES_1:8; hence contradiction by TREES_1: 16; end; Lm4: VERUM <> 'not' A & VERUM <> (#)A & VERUM <> A '&' B proof set e1 = elementary_tree 1; set e2 = elementary_tree 2; A1: dom VERUM = elementary_tree 0 by Def16,FUNCOP_1:19; set E = e1 --> [1,0]; set F = e1 --> [1,1]; A2: <*0*> in e1 by Th9,TARSKI:def 2; A3: dom E = e1 & dom F = e1 by FUNCOP_1:19; A4: <*0*> in dom E & <*0*> in dom F by A2,FUNCOP_1:19; A5: 'not' A = E with-replacement (<*0*>,A) by Def9; A6: (#)A = F with-replacement (<*0*>,A) by Def10; A7: dom 'not' A = dom E with-replacement (<*0*>,dom A) by A4,A5,TREES_2:def 12; A8: dom (#)A = dom F with-replacement (<*0*>,dom A) by A4,A6,TREES_2:def 12; A9: <*0*> in dom ('not' A) by A2,A3,A7,TREES_1:def 12; A10: <*0*> in dom ((#)A) by A2,A3,A8,TREES_1:def 12; thus VERUM <> 'not' A proof assume not thesis; then <*0*> = {} by A1,A9,TARSKI:def 1,TREES_1:56; hence contradiction by TREES_1:4; end; thus VERUM <> (#)A proof assume not thesis; then <*0*> = {} by A1,A10,TARSKI:def 1,TREES_1:56; hence contradiction by TREES_1:4; end; set y = (e2-->[2,0]) with-replacement (<*0*>,A); A11: A '&' B = y with-replacement (<*1*>,B) by Def11; A12: <*0*> in e2 & <*1*> in e2 by TREES_1:55; A13: dom (e2 --> [2,0]) = e2 by FUNCOP_1:19; then A14: dom y = dom( e2-->[2,0]) with-replacement (<*0*>,dom A) by A12,TREES_2:def 12; not <*0*> is_a_proper_prefix_of <*1*> by Th7; then A15: <*1*> in dom y by A12,A13,A14,TREES_1:def 12; then dom (A '&' B) = dom y with-replacement (<*1*>,dom B) by A11,TREES_2:def 12; then A16: <*1*> in dom (A '&' B) by A15,TREES_1:def 12; assume not thesis; then <*1*> = {} by A1,A16,TARSKI:def 1,TREES_1:56; hence contradiction by TREES_1:4; end; Lm5: [0,0] is MP-conective proof 0 in {0,1,2} & 0 in NAT by ENUMSET1:14; hence thesis by Def4,ZFMISC_1:106; end; Lm6: VERUM <> @p proof @p = elementary_tree 0 --> p by Def15; then A1: rng @p = {p} by FUNCOP_1:14; A2: rng VERUM = {[0,0]} by Def16,FUNCOP_1:14; assume not thesis; then [0,0] in {p} by A1,A2,TARSKI:def 1; hence contradiction by Lm5,Th31,XBOOLE_0:3; end; theorem VERUM <> @p & VERUM <> 'not' A & VERUM <> (#)A & VERUM <> A '&' B by Lm4,Lm6; scheme MP_Func_Ex{ D() -> non empty set, d() -> Element of D(), F(Element of MP-variables) -> Element of D(), N,H(Element of D()) -> Element of D(), C((Element of D()),Element of D()) -> Element of D() }: ex f being Function of MP-WFF, D() st f.VERUM = d() & (for p being MP-variable holds f.@p = F(p)) & (for A being Element of MP-WFF holds f.('not' A) = N(f.A)) & (for A being Element of MP-WFF holds f.((#)A) = H(f.A)) & (for A,B being Element of MP-WFF holds f.(A '&' B) = C(f.A,f.B)) proof defpred Pfgp[(Element of D()),(Function of MP-WFF,D()),Element of MP-WFF] means ($3 = VERUM implies $1 = d()) & (for p st $3 = @p holds $1 = F(p)) & (for A st $3 = 'not' A holds $1 = N($2.A)) & (for A st $3 = (#)A holds $1 = H($2.A)) & (for A,B st $3 = A '&' B holds $1 = C($2.A,$2.B)); defpred Pfn[(Function of MP-WFF, D()), Nat] means for A st card dom A <= $2 holds (A = VERUM implies $1.A = d()) & (for p st A = @p holds $1.A = F(p)) & (for B st A = 'not' B holds $1.A = N($1.B)) & (for B st A = (#)B holds $1.A = H($1.B)) & (for B,C st A = B '&' C holds $1.A = C($1.B,$1.C)); defpred P[Nat] means ex F be Function of MP-WFF,D() st Pfn[F,$1]; A1: P[0] proof consider F be Function of MP-WFF,D(); take F; let A such that A2: card dom A <= 0; card dom A = 0 by A2,NAT_1:18; hence thesis by CARD_2:59; end; A3: for k st P[k] holds P[k+1] proof let k; given F be Function of MP-WFF,D() such that A4: Pfn[F,k]; defpred Q[Element of MP-WFF,Element of D()] means (card dom $1 <> k+1 implies $2 = F.$1) & (card dom $1 = k+1 implies Pfgp[$2, F, $1]); A5: for x being Element of MP-WFF ex y being Element of D() st Q[x,y] proof let A be Element of MP-WFF; now per cases by Th48; case card dom A <> k+1; take y=F.A; case A6: card dom A = k+1 & A = VERUM; take y = d(); thus Pfgp[y,F,A] by A6,Lm4,Lm6; case card dom A = k + 1 & ex p st A = @p; then consider p such that A7: A = @p; take y = F(p); thus Pfgp[y,F,A] by A7,Lm6,Th37,Th49; case card dom A = k + 1 & ex B st A = 'not' B; then consider B such that A8: A = 'not' B; take y = N(F.B); thus Pfgp[y,F,A] by A8,Lm4,Th38,Th49,Th50; case card dom A = k + 1 & ex B st A = (#)B; then consider B such that A9: A = (#)B; take y = H(F.B); thus Pfgp[y,F,A] by A9,Lm4,Th39,Th49,Th50,Th51; case card dom A = k + 1 & ex B,C st A = B '&' C; then consider B,C such that A10: A = B '&' C; take y = C(F.B,F.C); now now let B1,C1; assume A = B1 '&' C1; then B=B1 & C=C1 by A10,Th40; hence y=C(F.B1,F.C1); end; hence Pfgp[y,F,A] by A10,Lm4,Th49,Th50,Th51; end; hence Pfgp[y,F,A]; end; hence ex y be Element of D() st (card dom A <> k +1 implies y = F.A) & (card dom A = k + 1 implies Pfgp[y,F,A]); end; consider G being Function of MP-WFF, D() such that A11: for p being Element of MP-WFF holds Q[p,G.p] from FuncExD(A5); take H = G; thus Pfn[H, k+1] proof let A be Element of MP-WFF; set p = card dom A; assume A12: p <= k+1; thus A = VERUM implies H.A = d() proof per cases; suppose A13: p <> k+1; then A14: p <= k by A12,NAT_1:26; H.A = F.A by A11,A13; hence thesis by A4,A14; suppose p = k+1; hence thesis by A11; end; thus for p st A = @p holds H.A = F(p) proof let q such that A15: A = @q; per cases; suppose A16: p <> k+1; then A17: p <= k by A12,NAT_1:26; H.A = F.A by A11,A16; hence thesis by A4,A15,A17; suppose p = k+1; hence thesis by A11,A15; end; thus for B st A = 'not' B holds H.A = N(H.B) proof let B; assume A18: A = 'not' B; then card dom B <> k+1 by A12,Th44; then A19: H.B = F.B by A11; per cases; suppose A20: p <> k+1; then A21: p <= k by A12,NAT_1:26; H.A = F.A by A11,A20; hence thesis by A4,A18,A19,A21; suppose p = k+1; hence thesis by A11,A18,A19; end; thus for B st A = (#)B holds H.A = H(H.B) proof let B; assume A22: A = (#)B; then card dom B <> k+1 by A12,Th45; then A23: H.B = F.B by A11; per cases; suppose A24: p <> k+1; then A25: p <= k by A12,NAT_1:26; H.A = F.A by A11,A24; hence thesis by A4,A22,A23,A25; suppose p = k+1; hence thesis by A11,A22,A23; end; thus for B,C st A = B '&' C holds H.A = C(H.B,H.C) proof let B,C; assume A26: A = B '&' C; then (card dom B) <> k+1 by A12,Th46; then A27: H.B = F.B by A11; (card dom C) <> k+1 by A12,A26,Th46; then A28: H.C = F.C by A11; per cases; suppose A29: p <> k+1; then A30: p <= k by A12,NAT_1:26; H.A = F.A by A11,A29; hence thesis by A4,A26,A27,A28,A30; suppose p = k+1; hence thesis by A11,A26,A27,A28; end; end; end; A31: for n holds P[n] from Ind(A1,A3); defpred Qfn[set, set] means ex A being Element of MP-WFF st A = $1 & for g being Function of MP-WFF, D() st Pfn[g, card dom A] holds $2 = g.A; A32: for x, y1, y2 st x in MP-WFF & Qfn[x, y1] & Qfn[x, y2] holds y1 = y2 proof let x, y1, y2 such that x in MP-WFF and A33: Qfn[x, y1] and A34: Qfn[x, y2]; consider p being Element of MP-WFF such that A35: p = x and A36: for g being Function of MP-WFF, D() st Pfn[g, card dom p] holds y1 = g. p by A33; consider F being Function of MP-WFF, D() such that A37: Pfn[F, card dom p] by A31; thus y1 = F.p by A36,A37 .= y2 by A34,A35,A37; end; A38: for x st x in MP-WFF ex y st Qfn[x, y] proof let x; assume x in MP-WFF; then reconsider x' = x as Element of MP-WFF; consider F being Function of MP-WFF, D() such that A39: Pfn[F, card dom x'] by A31; take F.x, x'; thus x = x'; let G be Function of MP-WFF, D(); assume A40: Pfn[G, card dom x']; defpred Prop[Element of MP-WFF] means card dom $1 <= card dom x' implies F.$1 = G.$1; A41: Prop[VERUM] proof assume A42: card dom VERUM <= card dom x'; hence F.VERUM = d() by A39 .= G.VERUM by A40,A42; end; A43: for p holds Prop[@p] proof let p; assume A44: card dom @p <= card dom x'; hence F.@p = F(p) by A39 .= G.@p by A40,A44; end; A45: for A be Element of MP-WFF st Prop[A] holds Prop['not' A] proof let A such that A46: Prop[A]; assume A47: card dom 'not' A <= card dom x'; card dom A < card dom 'not' A by Th44; hence F.('not' A) = N(G.A) by A39,A46,A47,AXIOMS:22 .= G.('not' A) by A40,A47; end; A48: for A be Element of MP-WFF st Prop[A] holds Prop[(#) A] proof let A such that A49: Prop[A]; assume A50: card dom (#)A <= card dom x'; card dom A < card dom (#)A by Th45; hence F.((#)A) = H(G.A) by A39,A49,A50,AXIOMS:22 .= G.((#)A) by A40,A50; end; A51: for A,B be Element of MP-WFF st Prop[A] & Prop[B] holds Prop[A '&' B] proof let A,B; assume that A52: Prop[A] and A53: Prop[B] and A54: card dom A '&' B <= card dom x'; A55: card dom A < card dom A '&' B by Th46; card dom B < card dom A '&' B by Th46; hence F.(A '&' B) = C(G.A, G.B) by A39,A52,A53,A54,A55,AXIOMS:22 .= G.(A '&' B) by A40,A54; end; for p be Element of MP-WFF holds Prop[p] from MP_Ind(A41,A43,A45,A48,A51); hence F.x = G.x'; end; consider F being Function such that A56: dom F = MP-WFF and A57: for x st x in MP-WFF holds Qfn[x, F.x] from FuncEx(A32,A38); F is Function of MP-WFF, D() proof rng F c= D() proof let y; assume y in rng F; then consider x being set such that A58: x in MP-WFF and A59: y = F.x by A56,FUNCT_1:def 5; consider p being Element of MP-WFF such that p = x and A60: for g being Function of MP-WFF, D() st Pfn[g, card dom p] holds y = g.p by A57,A58,A59; consider G being Function of MP-WFF, D() such that A61: Pfn[G, card dom p] by A31; y = G.p by A60,A61; hence y in D(); end; hence thesis by A56,FUNCT_2:def 1,RELSET_1:11; end; then reconsider F as Function of MP-WFF, D(); take F; consider A such that A62: A = VERUM & for g being Function of MP-WFF,D() st Pfn[g,card dom A] holds F.VERUM = g.A by A57; consider G being Function of MP-WFF,D() such that A63: Pfn[G,card dom A] by A31; F.VERUM = G.VERUM by A62,A63; hence F.VERUM = d() by A62,A63; thus for p being MP-variable holds F.@p = F(p) proof let p be MP-variable; consider A such that A64: A = @p & for g being Function of MP-WFF,D() st Pfn[g,card dom A] holds F.@p = g.A by A57; consider G being Function of MP-WFF,D() such that A65: Pfn[G,card dom A] by A31; F.@p = G.@p by A64,A65; hence thesis by A64,A65; end; thus for A being Element of MP-WFF holds F.('not' A) = N(F.A) proof let A be Element of MP-WFF; consider A1 such that A67: A1 = 'not' A & for g being Function of MP-WFF,D() st Pfn[g,card dom A1] holds F.'not' A = g.A1 by A57; consider G being Function of MP-WFF,D() such that A68: Pfn[G,card dom A1] by A31; A69: for k st k < card dom 'not' A holds Pfn[G,k] proof let k; assume A70: k < card dom 'not' A; let a be Element of MP-WFF; assume card dom a <= k; then card dom a <= card dom 'not' A by A70,AXIOMS:22; hence thesis by A67,A68; end; A71: F.'not' A = G.'not' A by A67,A68; set k = card dom A; k < card dom 'not' A by Th44; then A72: Pfn[G,k] by A69; ex B st B = A & for g be Function of MP-WFF,D() st Pfn[g,card dom B] holds F.A = g.B by A57; then F.A = G.A by A72; hence thesis by A67,A68,A71; end; thus for A being Element of MP-WFF holds F.((#)A) = H(F.A) proof let A be Element of MP-WFF; consider A1 such that A74: A1 = (#)A & for g being Function of MP-WFF,D() st Pfn[g,card dom A1] holds F.((#)A) = g.A1 by A57; consider G being Function of MP-WFF,D() such that A75: Pfn[G,card dom A1] by A31; A76: for k st k < card dom (#)A holds Pfn[G,k] proof let k; assume A77: k < card dom (#)A; let a be Element of MP-WFF; assume card dom a <= k; then card dom a <= card dom (#)A by A77,AXIOMS:22; hence thesis by A74,A75; end; A78: F.((#)A) = G.((#)A) by A74,A75; set k = card dom A; k < card dom (#)A by Th45; then A79: Pfn[G,k] by A76; ex B st B = A & for g be Function of MP-WFF,D() st Pfn[g,card dom B] holds F.A = g.B by A57; then F.A = G.A by A79; hence thesis by A74,A75,A78; end; thus for A,B being Element of MP-WFF holds F.(A '&' B) = C(F.A,F.B) proof let A,B be Element of MP-WFF; consider A1 such that A81: A1 = A '&' B & for g being Function of MP-WFF,D() st Pfn[g,card dom A1] holds F.(A '&' B) = g.A1 by A57; consider G being Function of MP-WFF,D() such that A82: Pfn[G,card dom A1] by A31; A83: for k st k < card dom A '&' B holds Pfn[G,k] proof let k; assume A84: k < card dom A '&' B; let a be Element of MP-WFF; assume card dom a <= k; then card dom a <= card dom A '&' B by A84,AXIOMS:22; hence thesis by A81,A82; end; A85: F.(A '&' B) = G.(A '&' B) by A81,A82; set k1 = card dom A; set k2 = card dom B; k1 < card dom A '&' B by Th46; then A86: Pfn[G,k1] by A83; ex B1 st B1 = A & for g be Function of MP-WFF,D() st Pfn[g,card dom B1] holds F.A = g.B1 by A57; then A87: F.A = G.A by A86; k2 < card dom A '&' B by Th46; then A88: Pfn[G,k2] by A83; ex C st C = B & for g be Function of MP-WFF,D() st Pfn[g,card dom C] holds F.B = g.C by A57; then F.B = G.B by A88; hence thesis by A81,A82,A85,A87; end; end;