Copyright (c) 1999 Association of Mizar Users
environ vocabulary FINSEQ_1, FINSEQ_2, EUCLID, FUNCT_1, PROB_1, FUNCT_6, RELAT_1, MATRLIN, PRALG_1, TARSKI, FINSET_1, MATRIX_1, TREES_1, CARD_1, CARD_2, GOBOARD1, MCART_1, ARYTM_1, GOBOARD5, GOBOARD2, PRE_TOPC, BOOLE, TOPREAL1, ABSVALUE, RFINSEQ, GOBRD13, FINSEQ_4; notation TARSKI, XBOOLE_0, ZFMISC_1, SUBSET_1, XREAL_0, REAL_1, NAT_1, BINARITH, ABSVALUE, STRUCT_0, RELAT_1, FUNCT_1, FUNCT_2, CARD_1, CARD_2, FINSEQ_1, FINSEQ_2, MATRLIN, PRALG_1, FINSEQ_4, FINSET_1, PROB_1, FUNCT_6, RFINSEQ, MATRIX_1, PRE_TOPC, EUCLID, TOPREAL1, GOBOARD1, GOBOARD2, GOBOARD5; constructors REAL_1, ABSVALUE, RFINSEQ, SEQM_3, BINARITH, CARD_2, GOBOARD2, GOBOARD5, PRALG_1, MATRLIN, WELLORD2, PROB_1, MEMBERED; clusters STRUCT_0, RELSET_1, EUCLID, GOBOARD2, GOBOARD5, FINSEQ_1, CARD_1, MEMBERED, NUMBERS, ORDINAL2; requirements NUMERALS, REAL, BOOLE, SUBSET, ARITHM; definitions TARSKI, PRALG_1, MATRLIN; theorems ZFMISC_1, NAT_1, FINSEQ_1, MATRIX_1, GOBOARD1, EUCLID, FINSEQ_3, AXIOMS, REAL_1, TARSKI, JORDAN3, FINSEQ_5, GOBOARD7, TOPREAL1, BINARITH, AMI_5, RLVECT_1, GOBOARD5, ABSVALUE, FUNCT_1, GOBOARD9, FINSEQ_2, PROB_1, GOBRD11, GOBOARD2, SPRECT_3, JORDAN5D, CARD_2, CARD_4, FINSET_1, YELLOW_6, FUNCT_6, RFINSEQ, JORDAN8, EXTENS_1, MATRLIN, CARD_1, PRE_CIRC, PARTFUN2, XCMPLX_1; schemes FRAENKEL; begin reserve i,i1,i2,i',i1',j,j1,j2,j',j1',k,k1,k2,l,m,n for Nat; reserve r,s,r',s' for Real; reserve D for non empty set, f for FinSequence of D; definition let E be non empty set; let S be FinSequence-DOMAIN of the carrier of TOP-REAL 2; let F be Function of E,S; let e be Element of E; redefine func F.e -> FinSequence of TOP-REAL 2; coherence proof thus F.e is FinSequence of TOP-REAL 2 by FINSEQ_2:def 3; end; end; definition let F be Function; func Values F -> set equals :Def1: Union rngs F; correctness; end; theorem Th1: for M being FinSequence of D* holds M.i is FinSequence of D proof let M be FinSequence of D*; per cases; suppose not i in dom M; then M.i = <*>D by FUNCT_1:def 4; hence thesis; suppose i in dom M; then A1: M.i in rng M by FUNCT_1:def 5; rng M c= D* by FINSEQ_1:def 4; hence thesis by A1,FINSEQ_1:def 11; end; definition let D be set; cluster -> FinSequence-yielding FinSequence of D*; coherence proof let f be FinSequence of D*; let x be set; assume x in dom f; then f.x in D* by FINSEQ_2:13; hence f.x is FinSequence by FINSEQ_1:def 11; end; end; definition cluster FinSequence-yielding -> Function-yielding Function; coherence proof let f be Function; assume A1: f is FinSequence-yielding; let x be set; thus thesis by A1,MATRLIN:def 1; end; end; canceled; theorem Th3: for M being FinSequence of D* holds Values M = union {rng f where f is Element of D*: f in rng M} proof let M be FinSequence of D*; set R = {rng f where f is Element of D*: f in rng M}; A1: Values M = Union rngs M by Def1; A2: Union rngs M = union rng rngs M by PROB_1:def 3; now let y be set; hereby assume y in Values M; then consider Y being set such that A3: y in Y and A4: Y in rng rngs M by A1,A2,TARSKI:def 4; consider i being set such that A5: i in dom rngs M and A6: (rngs M).i = Y by A4,FUNCT_1:def 5; A7: i in dom M by A5,EXTENS_1:4; then reconsider i as Nat; reconsider f = M.i as FinSequence of D by Th1; f in rng M & f in D* by A7,FINSEQ_1:def 11,FUNCT_1:def 5; then A8: rng f in R; Y = rng f by A6,A7,FUNCT_6:31; hence y in union R by A3,A8,TARSKI:def 4; end; assume y in union R; then consider Y being set such that A9: y in Y and A10: Y in R by TARSKI:def 4; consider f being Element of D* such that A11: Y = rng f and A12: f in rng M by A10; consider i such that A13: i in dom M and A14: M.i = f by A12,FINSEQ_2:11; i in dom rngs M & (rngs M).i = rng f by A13,A14,FUNCT_6:31; then rng f in rng rngs M by FUNCT_1:def 5; hence y in Values M by A1,A2,A9,A11,TARSKI:def 4; end; hence thesis by TARSKI:2; end; definition let D be non empty set, M be FinSequence of D*; cluster Values M -> finite; coherence proof deffunc F(Function) = rng $1; set A = {F(f) where f is Element of D*: f in rng M}; A1: rng M is finite; A2: {F(f) where f is Element of D*: f in rng M} is finite from FraenkelFin(A1); now let X be set; assume X in A; then ex f being Element of D* st X = rng f & f in rng M; hence X is finite; end; then union A is finite by A2,FINSET_1:25; hence thesis by Th3; end; end; theorem Th4: for M being Matrix of D st i in dom M & M.i = f holds len f = width M proof let M be Matrix of D such that A1: i in dom M and A2: M.i = f; A3: M.i in rng M by A1,FUNCT_1:def 5; M is non empty by A1,FINSEQ_1:26; then len M <> 0 by FINSEQ_1:25; then len M > 0 by NAT_1:19; then consider p being FinSequence such that A4: p in rng M and A5: len p = width M by MATRIX_1:def 4; consider n being Nat such that A6: for x being set st x in rng M ex s being FinSequence st s=x & len s = n by MATRIX_1:def 1; A7: ex s being FinSequence st s = p & len s = n by A4,A6; ex s being FinSequence st s = M.i & len s = n by A3,A6; hence thesis by A2,A5,A7; end; theorem Th5: for M being Matrix of D st i in dom M & M.i = f & j in dom f holds [i,j] in Indices M proof let M be Matrix of D such that A1: i in dom M and A2: M.i = f and A3: j in dom f; A4: M.i in rng M by A1,FUNCT_1:def 5; M is non empty by A1,FINSEQ_1:26; then len M <> 0 by FINSEQ_1:25; then len M > 0 by NAT_1:19; then consider p being FinSequence such that A5: p in rng M and A6: len p = width M by MATRIX_1:def 4; consider n being Nat such that A7: for x being set st x in rng M ex s being FinSequence st s=x & len s = n by MATRIX_1:def 1; A8: ex s being FinSequence st s = p & len s = n by A5,A7; A9: Indices M = [:dom M,Seg width M:] by MATRIX_1:def 5; ex s being FinSequence st s = M.i & len s = n by A4,A7; then j in Seg width M by A2,A3,A6,A8,FINSEQ_1:def 3; hence thesis by A1,A9,ZFMISC_1:106; end; theorem Th6: for M being Matrix of D st [i,j] in Indices M & M.i = f holds len f = width M & j in dom f proof let M be Matrix of D such that A1: [i,j] in Indices M; A2: Indices M = [:dom M,Seg width M:] by MATRIX_1:def 5; then A3: i in dom M by A1,ZFMISC_1:106; then A4: M.i in rng M by FUNCT_1:def 5; A5: j in Seg width M by A1,A2,ZFMISC_1:106; M is non empty by A3,FINSEQ_1:26; then len M <> 0 by FINSEQ_1:25; then len M > 0 by NAT_1:19; then consider p being FinSequence such that A6: p in rng M and A7: len p = width M by MATRIX_1:def 4; consider n being Nat such that A8: for x being set st x in rng M ex s being FinSequence st s=x & len s = n by MATRIX_1:def 1; A9: ex s being FinSequence st s = p & len s = n by A6,A8; ex s being FinSequence st s = M.i & len s = n by A4,A8; hence thesis by A5,A7,A9,FINSEQ_1:def 3; end; theorem Th7: for M being Matrix of D holds Values M = { M*(i,j): [i,j] in Indices M } proof let M be Matrix of D; set V = { M*(i,j): [i,j] in Indices M }, R = {rng f where f is Element of D*: f in rng M}; A1: Values M = union R by Th3; now let y be set; hereby assume y in Values M; then consider Y being set such that A2: y in Y and A3: Y in R by A1,TARSKI:def 4; consider f being Element of D* such that A4: Y = rng f and A5: f in rng M by A3; consider i such that A6: i in dom M and A7: M.i = f by A5,FINSEQ_2:11; consider j such that A8: j in dom f and A9: f.j = y by A2,A4,FINSEQ_2:11; A10: [i,j] in Indices M by A6,A7,A8,Th5; then ex p being FinSequence of D st p = M.i & M*(i,j) = p.j by MATRIX_1:def 6; hence y in V by A7,A9,A10; end; assume y in V; then consider i,j such that A11: y = M*(i,j) and A12: [i,j] in Indices M; consider f being FinSequence of D such that A13: f = M.i and A14: M*(i,j) = f.j by A12,MATRIX_1:def 6; Indices M = [:dom M,Seg width M:] by MATRIX_1:def 5; then i in dom M by A12,ZFMISC_1:106; then A15: M.i in rng M by FUNCT_1:def 5; f in D* by FINSEQ_1:def 11; then A16: rng f in R by A13,A15; j in dom f by A12,A13,Th6; then f.j in rng f by FUNCT_1:def 5; hence y in Values M by A1,A11,A14,A16,TARSKI:def 4; end; hence thesis by TARSKI:2; end; theorem for D being non empty set, M being Matrix of D holds card Values M <= (len M)*(width M) proof let D be non empty set, M be Matrix of D; A1: Card dom rngs M = Card dom M by EXTENS_1:4 .= Card M by PRE_CIRC:21 .= Card len M by CARD_1:def 5; now let x be set; assume x in dom rngs M; then A2: x in dom M by EXTENS_1:4; then reconsider i = x as Nat; reconsider f = M.i as FinSequence of D by Th1; Card rng f c= Card dom f by YELLOW_6:3; then Card rng f c= Card Seg len f by FINSEQ_1:def 3; then Card rng f c= Card len f by FINSEQ_1:76; then Card rng f c= Card width M by A2,Th4; hence Card ((rngs M).x) c= Card width M by A2,FUNCT_6:31; end; then Card Union rngs M c= Card(len M)*`Card(width M) by A1,CARD_4:59; then Card Values M c= Card(len M)*`Card(width M) by Def1; then Card Values M c= Card((len M)*(width M)) by CARD_2:52; then card Values M <= card((len M)*(width M)) by CARD_2:57; hence card Values M <= (len M)*(width M) by FINSEQ_1:78; end; reserve f for FinSequence of TOP-REAL 2, G for Go-board; theorem for G being Matrix of TOP-REAL 2 holds f is_sequence_on G implies rng f c= Values G proof let G be Matrix of TOP-REAL 2; assume A1: f is_sequence_on G; let y be set; assume y in rng f; then consider n such that A2: n in dom f and A3: f/.n = y by PARTFUN2:4; ex i,j st [i,j] in Indices G & f/.n = G*(i,j) by A1,A2,GOBOARD1:def 11; then y in { G*(i,j): [i,j] in Indices G } by A3; hence thesis by Th7; end; theorem Th10: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & 1 <= j2 & j2 <= width G2 & G1*(i1,j1) = G2*(1,j2) holds i1 = 1 proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: 1 <= j2 & j2 <= width G2 and A4: G1*(i1,j1) = G2*(1,j2); A5: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; 0 <> len G2 by GOBOARD1:def 5; then A6: 1 <= len G2 by RLVECT_1:99; 0 <> len G1 by GOBOARD1:def 5; then A7: 1 <= len G1 by RLVECT_1:99; set p = G1*(1,j1); assume i1 <> 1; then 1 < i1 by A5,REAL_1:def 5; then A8: p`1 < G1*(i1,j1)`1 by A5,GOBOARD5:4; [1,j1] in Indices G1 by A5,A7,GOBOARD7:10; then p in {G1*(i,j): [i,j] in Indices G1}; then p in Values G1 by Th7; then p in Values G2 by A1; then p in {G2*(i,j): [i,j] in Indices G2} by Th7; then consider i,j such that A9: p = G2*(i,j) and A10: [i,j] in Indices G2; A11: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A10,GOBOARD5:1; then A12: G2*(1,j)`1 = G2*(1,1)`1 by A6,GOBOARD5:3 .= G2*(1,j2)`1 by A3,A6,GOBOARD5:3; then 1 < i by A4,A8,A9,A11,REAL_1:def 5; hence contradiction by A4,A8,A9,A11,A12,GOBOARD5:4; end; theorem Th11: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & 1 <= j2 & j2 <= width G2 & G1*(i1,j1) = G2*(len G2,j2) holds i1 = len G1 proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: 1 <= j2 & j2 <= width G2 and A4: G1*(i1,j1) = G2*(len G2,j2); A5: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; 0 <> len G2 by GOBOARD1:def 5; then A6: 1 <= len G2 by RLVECT_1:99; 0 <> len G1 by GOBOARD1:def 5; then A7: 1 <= len G1 by RLVECT_1:99; set p = G1*(len G1,j1); assume i1 <> len G1; then i1 < len G1 by A5,REAL_1:def 5; then A8: G1*(i1,j1)`1 < p`1 by A5,GOBOARD5:4; [len G1,j1] in Indices G1 by A5,A7,GOBOARD7:10; then p in {G1*(i,j): [i,j] in Indices G1}; then p in Values G1 by Th7; then p in Values G2 by A1; then p in {G2*(i,j): [i,j] in Indices G2} by Th7; then consider i,j such that A9: p = G2*(i,j) and A10: [i,j] in Indices G2; A11: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A10,GOBOARD5:1; then A12: G2*(len G2,j)`1 = G2*(len G2,1)`1 by A6,GOBOARD5:3 .= G2*(len G2,j2)`1 by A3,A6,GOBOARD5:3; then i < len G2 by A4,A8,A9,A11,REAL_1:def 5; hence contradiction by A4,A8,A9,A11,A12,GOBOARD5:4; end; theorem Th12: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & 1 <= i2 & i2 <= len G2 & G1*(i1,j1) = G2*(i2,1) holds j1 = 1 proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: 1 <= i2 & i2 <= len G2 and A4: G1*(i1,j1) = G2*(i2,1); A5: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; 0 <> width G2 by GOBOARD1:def 5; then A6: 1 <= width G2 by RLVECT_1:99; 0 <> width G1 by GOBOARD1:def 5; then A7: 1 <= width G1 by RLVECT_1:99; set p = G1*(i1,1); assume j1 <> 1; then 1 < j1 by A5,REAL_1:def 5; then A8: p`2 < G1*(i1,j1)`2 by A5,GOBOARD5:5; [i1,1] in Indices G1 by A5,A7,GOBOARD7:10; then p in {G1*(i,j): [i,j] in Indices G1}; then p in Values G1 by Th7; then p in Values G2 by A1; then p in {G2*(i,j): [i,j] in Indices G2} by Th7; then consider i,j such that A9: p = G2*(i,j) and A10: [i,j] in Indices G2; A11: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A10,GOBOARD5:1; then A12: G2*(i,1)`2 = G2*(1,1)`2 by A6,GOBOARD5:2 .= G2*(i2,1)`2 by A3,A6,GOBOARD5:2; then 1 < j by A4,A8,A9,A11,REAL_1:def 5; hence contradiction by A4,A8,A9,A11,A12,GOBOARD5:5; end; theorem Th13: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & 1 <= i2 & i2 <= len G2 & G1*(i1,j1) = G2*(i2,width G2) holds j1 = width G1 proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: 1 <= i2 & i2 <= len G2 and A4: G1*(i1,j1) = G2*(i2,width G2); A5: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; 0 <> width G2 by GOBOARD1:def 5; then A6: 1 <= width G2 by RLVECT_1:99; 0 <> width G1 by GOBOARD1:def 5; then A7: 1 <= width G1 by RLVECT_1:99; set p = G1*(i1,width G1); assume j1 <> width G1; then j1 < width G1 by A5,REAL_1:def 5; then A8: G1*(i1,j1)`2 < p`2 by A5,GOBOARD5:5; [i1,width G1] in Indices G1 by A5,A7,GOBOARD7:10; then p in {G1*(i,j): [i,j] in Indices G1}; then p in Values G1 by Th7; then p in Values G2 by A1; then p in {G2*(i,j): [i,j] in Indices G2} by Th7; then consider i,j such that A9: p = G2*(i,j) and A10: [i,j] in Indices G2; A11: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A10,GOBOARD5:1; then A12: G2*(i,width G2)`2 = G2*(1,width G2)`2 by A6,GOBOARD5:2 .= G2*(i2,width G2)`2 by A3,A6,GOBOARD5:2; then j < width G2 by A4,A8,A9,A11,REAL_1:def 5; hence contradiction by A4,A8,A9,A11,A12,GOBOARD5:5; end; theorem Th14: for G1,G2 being Go-board st Values G1 c= Values G2 & 1 <= i1 & i1 < len G1 & 1 <= j1 & j1 <= width G1 & 1 <= i2 & i2 < len G2 & 1 <= j2 & j2 <= width G2 & G1*(i1,j1) = G2*(i2,j2) holds G2*(i2+1,j2)`1 <= G1*(i1+1,j1)`1 proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: 1 <= i1 & i1 < len G1 and A3: 1 <= j1 & j1 <= width G1 and A4: 1 <= i2 & i2 < len G2 and A5: 1 <= j2 & j2 <= width G2 and A6: G1*(i1,j1) = G2*(i2,j2); set p = G1*(i1+1,j1); assume A7: p`1 < G2*(i2+1,j2)`1; A8: 1 <= i1+1 & i1 < i1+1 & i1+1 <= len G1 by A2,NAT_1:38; then [i1+1,j1] in Indices G1 by A3,GOBOARD7:10; then p in {G1*(i,j): [i,j] in Indices G1}; then p in Values G1 by Th7; then p in Values G2 by A1; then p in {G2*(i,j): [i,j] in Indices G2} by Th7; then consider i,j such that A9: p = G2*(i,j) and A10: [i,j] in Indices G2; A11: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A10,GOBOARD5:1; then A12: G2*(i,j)`1 = G2*(i,1)`1 by GOBOARD5:3 .= G2*(i,j2)`1 by A5,A11,GOBOARD5:3; then A13: G2*(i2,j2)`1 < G2*(i,j2)`1 by A2,A3,A6,A8,A9,GOBOARD5:4; A14: now assume i <= i2; then i = i2 or i < i2 by REAL_1:def 5; hence contradiction by A4,A5,A11,A13,GOBOARD5:4; end; A15: 1 <= i2+1 & i2 < i2+1 & i2+1 <= len G2 by A4,NAT_1:38; now assume i2+1 <= i; then i2+1 = i or i2+1 < i by REAL_1:def 5; hence contradiction by A5,A7,A9,A11,A12,A15,GOBOARD5:4; end; hence contradiction by A14,NAT_1:38; end; theorem Th15: for G1,G2 being Go-board st G1*(i1-'1,j1) in Values G2 & 1 < i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 & 1 < i2 & i2 <= len G2 & 1 <= j2 & j2 <= width G2 & G1*(i1,j1) = G2*(i2,j2) holds G1*(i1-'1,j1)`1 <= G2*(i2-'1,j2)`1 proof let G1,G2 be Go-board such that A1: G1*(i1-'1,j1) in Values G2 and A2: 1 < i1 & i1 <= len G1 and A3: 1 <= j1 & j1 <= width G1 and A4: 1 < i2 & i2 <= len G2 and A5: 1 <= j2 & j2 <= width G2 and A6: G1*(i1,j1) = G2*(i2,j2); set p = G1*(i1-'1,j1); assume A7: G2*(i2-'1,j2)`1 < p`1; A8: 1 <= i1-'1 by A2,JORDAN3:12; then A9: i1-'1 < i1 by JORDAN3:14; p in {G2*(i,j): [i,j] in Indices G2} by A1,Th7; then consider i,j such that A10: p = G2*(i,j) and A11: [i,j] in Indices G2; A12: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A11,GOBOARD5:1; then A13: G2*(i,j)`1 = G2*(i,1)`1 by GOBOARD5:3 .= G2*(i,j2)`1 by A5,A12,GOBOARD5:3; then A14: G2*(i,j2)`1 < G2*(i2,j2)`1 by A2,A3,A6,A8,A9,A10,GOBOARD5:4; A15: now assume i2 <= i; then i = i2 or i2 < i by REAL_1:def 5; hence contradiction by A4,A5,A12,A14,GOBOARD5:4; end; 1 <= i2-'1 by A4,JORDAN3:12; then i2-'1 < i2 by JORDAN3:14; then A16: i2-'1 < len G2 by A4,AXIOMS:22; now assume i <= i2-'1; then i2-'1 = i or i < i2-'1 by REAL_1:def 5; hence contradiction by A5,A7,A10,A12,A13,A16,GOBOARD5:4; end; hence contradiction by A15,JORDAN3:12; end; theorem Th16: for G1,G2 being Go-board st G1*(i1,j1+1) in Values G2 & 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 < width G1 & 1 <= i2 & i2 <= len G2 & 1 <= j2 & j2 < width G2 & G1*(i1,j1) = G2*(i2,j2) holds G2*(i2,j2+1)`2 <= G1*(i1,j1+1)`2 proof let G1,G2 be Go-board such that A1: G1*(i1,j1+1) in Values G2 and A2: 1 <= i1 & i1 <= len G1 and A3: 1 <= j1 & j1 < width G1 and A4: 1 <= i2 & i2 <= len G2 and A5: 1 <= j2 & j2 < width G2 and A6: G1*(i1,j1) = G2*(i2,j2); set p = G1*(i1,j1+1); assume A7: p`2 < G2*(i2,j2+1)`2; A8: 1 <= j1+1 & j1 < j1+1 & j1+1 <= width G1 by A3,NAT_1:38; p in {G2*(i,j): [i,j] in Indices G2} by A1,Th7; then consider i,j such that A9: p = G2*(i,j) and A10: [i,j] in Indices G2; A11: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A10,GOBOARD5:1; then A12: G2*(i,j)`2 = G2*(1,j)`2 by GOBOARD5:2 .= G2*(i2,j)`2 by A4,A11,GOBOARD5:2; then A13: G2*(i2,j2)`2 < G2*(i2,j)`2 by A2,A3,A6,A8,A9,GOBOARD5:5; A14: now assume j <= j2; then j = j2 or j < j2 by REAL_1:def 5; hence contradiction by A4,A5,A11,A13,GOBOARD5:5; end; A15: 1 <= j2+1 & j2 < j2+1 & j2+1 <= width G2 by A5,NAT_1:38; now assume j2+1 <= j; then j2+1 = j or j2+1 < j by REAL_1:def 5; hence contradiction by A4,A7,A9,A11,A12,A15,GOBOARD5:5; end; hence contradiction by A14,NAT_1:38; end; theorem Th17: for G1,G2 being Go-board st Values G1 c= Values G2 & 1 <= i1 & i1 <= len G1 & 1 < j1 & j1 <= width G1 & 1 <= i2 & i2 <= len G2 & 1 < j2 & j2 <= width G2 & G1*(i1,j1) = G2*(i2,j2) holds G1*(i1,j1-'1)`2 <= G2*(i2,j2-'1)`2 proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: 1 <= i1 & i1 <= len G1 and A3: 1 < j1 & j1 <= width G1 and A4: 1 <= i2 & i2 <= len G2 and A5: 1 < j2 & j2 <= width G2 and A6: G1*(i1,j1) = G2*(i2,j2); set p = G1*(i1,j1-'1); assume A7: G2*(i2,j2-'1)`2 < p`2; A8: 1 <= j1-'1 by A3,JORDAN3:12; then A9: j1-'1 < j1 by JORDAN3:14; then j1-'1 < width G1 by A3,AXIOMS:22; then [i1,j1-'1] in Indices G1 by A2,A8,GOBOARD7:10; then p in {G1*(i,j): [i,j] in Indices G1}; then p in Values G1 by Th7; then p in Values G2 by A1; then p in {G2*(i,j): [i,j] in Indices G2} by Th7; then consider i,j such that A10: p = G2*(i,j) and A11: [i,j] in Indices G2; A12: 1 <= i & i <= len G2 & 1 <= j & j <= width G2 by A11,GOBOARD5:1; then A13: G2*(i,j)`2 = G2*(1,j)`2 by GOBOARD5:2 .= G2*(i2,j)`2 by A4,A12,GOBOARD5:2; then A14: G2*(i2,j)`2 < G2*(i2,j2)`2 by A2,A3,A6,A8,A9,A10,GOBOARD5:5; A15: now assume j2 <= j; then j = j2 or j2 < j by REAL_1:def 5; hence contradiction by A4,A5,A12,A14,GOBOARD5:5; end; 1 <= j2-'1 by A5,JORDAN3:12; then j2-'1 < j2 by JORDAN3:14; then A16: j2-'1 < width G2 by A5,AXIOMS:22; now assume j <= j2-'1; then j2-'1 = j or j < j2-'1 by REAL_1:def 5; hence contradiction by A4,A7,A10,A12,A13,A16,GOBOARD5:5; end; hence contradiction by A15,JORDAN3:12; end; Lm1: for M being Matrix of D st 1 <= i & i <= len M & 1 <= j & j <= width M holds M*(i,j) in Values M proof let M be Matrix of D; A1: Values M = { M*(i1,j1): [i1,j1] in Indices M } by Th7; assume 1 <= i & i <= len M & 1 <= j & j <= width M; then [i,j] in Indices M by GOBOARD7:10; hence thesis by A1; end; theorem Th18: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & [i2,j2] in Indices G2 & G1*(i1,j1) = G2*(i2,j2) holds cell(G2,i2,j2) c= cell(G1,i1,j1) proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: [i2,j2] in Indices G2 and A4: G1*(i1,j1) = G2*(i2,j2); let p be set such that A5: p in cell(G2,i2,j2); A6: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; A7: 1 <= i2 & i2 <= len G2 & 1 <= j2 & j2 <= width G2 by A3,GOBOARD5:1; A8: G1*(i1,j1)`1 = G1*(i1,1)`1 & G1*(i1,j1)`2 = G1*(1,j1)`2 by A6,GOBOARD5:2,3; A9: G2*(i2,j2)`1 = G2*(i2,1)`1 & G2*(i2,j2)`2 = G2*(1,j2)`2 by A7,GOBOARD5:2,3; per cases by A7,REAL_1:def 5; suppose A10: i2 = len G2 & j2 = width G2; then A11: i1 = len G1 & j1 = width G1 by A1,A2,A4,A7,Th11,Th13; p in { |[r,s]| : G2*(i2,j2)`1 <= r & G2*(i2,j2)`2 <= s } by A5,A9,A10,GOBRD11:28; hence p in cell(G1,i1,j1) by A4,A8,A11,GOBRD11:28; suppose A12: i2 = len G2 & j2 < width G2; then A13: i1 = len G1 by A1,A2,A4,A7,Th11; p in { |[r,s]| : G2*(i2,j2)`1 <= r & G2*(i2,j2)`2 <= s & s <= G2*(1,j2+1)`2 } by A5,A7,A9,A12,GOBRD11:29; then consider r',s' such that A14: p = |[r',s']| and A15: G2*(i2,j2)`1 <= r' & G2*(i2,j2)`2 <= s' and A16: s' <= G2*(1,j2+1)`2; now per cases by A6,REAL_1:def 5; suppose A17: j1 = width G1; p in { |[r,s]| : G1*(i1,j1)`1 <= r & G1*(i1,j1)`2 <= s} by A4,A14,A15; hence p in cell(G1,i1,j1) by A8,A13,A17,GOBRD11:28; suppose A18: j1 < width G1; then A19: 1 <= j1+1 & j1+1 <= width G1 & 1 <= j2+1 & j2+1 <= width G2 by A12,NAT_1:37,38; then A20: G1*(i1,j1+1) in Values G1 by A6,Lm1; G2*(i2,j2+1)`2 = G2*(1,j2+1)`2 & G1*(i1,j1+1)`2 = G1*(1,j1+1)`2 by A6,A7,A19,GOBOARD5:2; then G2*(1,j2+1)`2 <= G1*(1,j1+1)`2 by A1,A4,A6,A7,A12,A18,A20,Th16; then s' <= G1*(1,j1+1)`2 by A16,AXIOMS:22; then p in {|[r,s]| : G1*(i1,j1)`1 <= r & G1*(i1,j1)`2 <= s & s <= G1*(1,j1+1)`2} by A4,A14,A15; hence p in cell(G1,i1,j1) by A6,A8,A13,A18,GOBRD11:29; end; hence p in cell(G1,i1,j1); suppose A21: i2 < len G2 & j2 = width G2; then A22: j1 = width G1 by A1,A2,A4,A7,Th13; p in {|[r,s]|: G2*(i2,j2)`1 <= r & r <= G2*(i2+1,1)`1 & G2*(i2,j2)`2 <= s} by A5,A7,A9,A21,GOBRD11:31; then consider r',s' such that A23: p = |[r',s']| and A24: G2*(i2,j2)`1 <= r' and A25: r' <= G2*(i2+1,1)`1 and A26: G2*(i2,j2)`2 <= s'; now per cases by A6,REAL_1:def 5; suppose A27: i1 = len G1; p in { |[r,s]| : G1*(i1,j1)`1 <= r & G1*(i1,j1)`2 <= s} by A4,A23,A24,A26; hence p in cell(G1,i1,j1) by A8,A22,A27,GOBRD11:28; suppose A28: i1 < len G1; then 1 <= i1+1 & i1+1 <= len G1 & 1 <= i2+1 & i2+1 <= len G2 by A21,NAT_1:37,38; then G2*(i2+1,j2)`1 = G2*(i2+1,1)`1 & G1*(i1+1,j1)`1 = G1*(i1+1,1)`1 by A6,A7,GOBOARD5:3; then G2*(i2+1,1)`1 <= G1*(i1+1,1)`1 by A1,A4,A6,A7,A21,A28,Th14; then r' <= G1*(i1+1,1)`1 by A25,AXIOMS:22; then p in {|[r,s]|: G1*(i1,j1)`1 <= r & r <= G1*(i1+1,1)`1 & G1*(i1,j1)`2 <= s} by A4,A23,A24,A26; hence p in cell(G1,i1,j1) by A6,A8,A22,A28,GOBRD11:31; end; hence p in cell(G1,i1,j1); suppose A29: i2 < len G2 & j2 < width G2; then 1 <= i2+1 & i2+1 <= len G2 & 1 <= j2+1 & j2+1 <= width G2 by NAT_1:37,38 ; then G2*(i2+1,j2)`1 = G2*(i2+1,1)`1 & G2*(i2,j2+1)`2 = G2*(1,j2+1)`2 by A7,GOBOARD5:2,3; then p in { |[r,s]| : G2*(i2,j2)`1 <= r & r <= G2*(i2+1,j2)`1 & G2*(i2,j2)`2 <= s & s <= G2*(i2,j2+1)`2 } by A5,A7,A9,A29,GOBRD11:32; then consider r',s' such that A30: p = |[r',s']| and A31: G2*(i2,j2)`1 <= r' and A32: r' <= G2*(i2+1,j2)`1 and A33: G2*(i2,j2)`2 <= s' and A34: s' <= G2*(i2,j2+1)`2; now per cases by A6,REAL_1:def 5; suppose A35: i1 = len G1 & j1 = width G1; p in { |[r,s]| : G1*(i1,j1)`1 <= r & G1*(i1,j1)`2 <= s } by A4,A30,A31,A33; hence p in cell(G1,i1,j1) by A8,A35,GOBRD11:28; suppose A36: i1 = len G1 & j1 < width G1; then A37: 1 <= j1+1 & j1+1 <= width G1 by NAT_1:37,38; then A38: G1*(i1,j1+1) in Values G1 by A6,Lm1; G1*(i1,j1+1)`2 = G1*(1,j1+1)`2 by A6,A37,GOBOARD5:2; then G2*(i2,j2+1)`2 <= G1*(1,j1+1)`2 by A1,A4,A6,A7,A29,A36,A38,Th16; then s' <= G1*(1,j1+1)`2 by A34,AXIOMS:22; then p in {|[r,s]| : G1*(i1,j1)`1 <= r & G1*(i1,j1)`2 <= s & s <= G1* (1,j1+1)`2} by A4,A30,A31,A33; hence p in cell(G1,i1,j1) by A6,A8,A36,GOBRD11:29; suppose A39: i1 < len G1 & j1 = width G1; then 1 <= i1+1 & i1+1 <= len G1 by NAT_1:37,38; then G1*(i1+1,j1)`1 = G1*(i1+1,1)`1 by A6,GOBOARD5:3; then G2*(i2+1,j2)`1 <= G1*(i1+1,1)`1 by A1,A4,A6,A7,A29,A39,Th14; then r' <= G1*(i1+1,1)`1 by A32,AXIOMS:22; then p in {|[r,s]|: G1*(i1,j1)`1 <= r & r <= G1*(i1+1,1)`1 & G1*(i1,j1)`2 <= s} by A4,A30,A31,A33; hence p in cell(G1,i1,j1) by A6,A8,A39,GOBRD11:31; suppose A40: i1 < len G1 & j1 < width G1; then A41: 1 <= j1+1 & j1+1 <= width G1 & 1 <= i1+1 & i1+1 <= len G1 by NAT_1: 37,38; then A42: G1*(i1,j1+1) in Values G1 by A6,Lm1; G1*(i1,j1+1)`2 = G1*(1,j1+1)`2 & G1*(i1+1,j1)`1 = G1*(i1+1,1)`1 by A6,A41,GOBOARD5:2,3; then G2*(i2,j2+1)`2 <= G1*(1,j1+1)`2 & G2*(i2+1,j2)`1 <= G1*(i1+1,1)`1 by A1,A4,A6,A7,A29,A40,A42,Th14,Th16; then s' <= G1*(1,j1+1)`2 & r' <= G1*(i1+1,1)`1 by A32,A34,AXIOMS:22; then p in { |[r,s]| : G1*(i1,1)`1 <= r & r <= G1*(i1+1,1)`1 & G1*(1,j1)`2 <= s & s <= G1*(1,j1+1)`2 } by A4,A8,A30,A31,A33; hence p in cell(G1,i1,j1) by A6,A40,GOBRD11:32; end; hence p in cell(G1,i1,j1); end; theorem Th19: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & [i2,j2] in Indices G2 & G1*(i1,j1) = G2*(i2,j2) holds cell(G2,i2-'1,j2) c= cell(G1,i1-'1,j1) proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: [i2,j2] in Indices G2 and A4: G1*(i1,j1) = G2*(i2,j2); let p be set such that A5: p in cell(G2,i2-'1,j2); A6: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; A7: 1 <= i2 & i2 <= len G2 & 1 <= j2 & j2 <= width G2 by A3,GOBOARD5:1; then A8: G2*(i2,j2)`1 = G2*(i2,1)`1 & G2*(i2,j2)`2 = G2*(1,j2)`2 by GOBOARD5:2,3; per cases by A6,A7,REAL_1:def 5; suppose A9: i1 = 1 & i2 = 1; then A10: i1-'1 = 0 & i2-'1 = 0 by GOBOARD9:1; now per cases by A7,REAL_1:def 5; suppose A11: j2 = width G2; then p in { |[r,s]| : r <= G2*(1,1)`1 & G2*(1,width G2)`2 <= s } by A5,A10,GOBRD11:25; then consider r',s' such that A12: p = |[r',s']| and A13: r' <= G2*(1,1)`1 and A14: G2*(1,width G2)`2 <= s'; A15: j1 = width G1 by A1,A2,A4,A7,A11,Th13; G2*(1,1)`1 = G2*(i1,j2)`1 by A7,A9,GOBOARD5:3; then r' <= G1*(1,1)`1 by A4,A6,A9,A13,GOBOARD5:3; then p in { |[r,s]| : r <= G1*(1,1)`1 & G1*(1,width G1)`2 <= s } by A4,A9,A11,A12,A14,A15; hence thesis by A10,A15,GOBRD11:25; suppose A16: j2 < width G2; then p in {|[r,s]|: r <= G2*(1,1)`1 & G2*(1,j2)`2 <= s & s <= G2*(1,j2+1)`2} by A5,A7,A10,GOBRD11:26; then consider r',s' such that A17: p = |[r',s']| and A18: r' <= G2*(1,1)`1 and A19: G2*(1,j2)`2 <= s' and A20: s' <= G2*(1,j2+1)`2; G2*(1,1)`1 = G2*(i1,j2)`1 by A7,A9,GOBOARD5:3; then A21: r' <= G1*(1,1)`1 by A4,A6,A9,A18,GOBOARD5:3; now per cases by A6,REAL_1:def 5; suppose A22: j1 = width G1; then p in { |[r,s]| : r <= G1*(1,1)`1 & G1*(1,width G1)`2 <= s } by A4,A9,A17,A19,A21; hence thesis by A10,A22,GOBRD11:25; suppose A23: j1 < width G1; then 1 <= j1 + 1 & j1 + 1 <= width G1 by NAT_1:29,38; then G1*(i1,j1+1) in Values G1 by A6,Lm1; then G2*(1,j2+1)`2 <= G1*(1,j1+1)`2 by A1,A4,A6,A7,A9,A16,A23,Th16; then s' <= G1*(1,j1+1)`2 by A20,AXIOMS:22; then p in {|[r,s]|: r <= G1*(1,1)`1 & G1*(1,j1)`2 <= s & s <= G1*(1,j1+1)`2} by A4,A9,A17,A19,A21; hence thesis by A6,A10,A23,GOBRD11:26; end; hence thesis; end; hence thesis; suppose that A24: i1 = 1 and A25: 1 < i2; A26: i1-'1 = 0 by A24,GOBOARD9:1; A27: 1 <= i2-'1 by A25,JORDAN3:12; then i2-'1 < i2 by JORDAN3:14; then A28: i2-'1 < len G2 by A7,AXIOMS:22; A29: i2-'1+1 = i2 by A25,AMI_5:4; now per cases by A7,REAL_1:def 5; suppose A30: j2 = width G2; then p in { |[r,s]|: G2*(i2-'1,1)`1 <= r & r <= G2*(i2,1)`1 & G2*(1,j2)`2 <= s} by A5,A27,A28,A29,GOBRD11:31; then consider r',s' such that A31: p = |[r',s']| and G2*(i2-'1,1)`1 <= r' and A32: r' <= G2*(i2,1)`1 and A33: G2*(1,j2)`2 <= s'; A34: j1 = width G1 by A1,A2,A4,A7,A30,Th13; A35: r' <= G1*(1,1)`1 by A4,A6,A8,A24,A32,GOBOARD5:3; G1*(1,j1)`2 <= s' by A4,A6,A8,A33,GOBOARD5:2; then p in { |[r,s]| : r <= G1*(1,1)`1 & G1*(1,j1)`2 <= s } by A31,A35; hence thesis by A26,A34,GOBRD11:25; suppose A36: j2 < width G2; then p in { |[r,s]| : G2*(i2-'1,1)`1 <= r & r <= G2*(i2,1)`1 & G2*(1,j2)`2 <= s & s <= G2*(1,j2+1)`2 } by A5,A7,A27,A28,A29,GOBRD11:32; then consider r',s' such that A37: p = |[r',s']| and G2*(i2-'1,1)`1 <= r' and A38: r' <= G2*(i2,1)`1 and A39: G2*(1,j2)`2 <= s' and A40: s' <= G2*(1,j2+1)`2; A41: r' <= G1*(1,1)`1 by A4,A6,A8,A24,A38,GOBOARD5:3; A42: G1*(1,j1)`2 <= s' by A4,A6,A8,A39,GOBOARD5:2; now per cases by A6,REAL_1:def 5; suppose A43: j1 = width G1; then p in { |[r,s]| : r <= G1*(1,1)`1 & G1*(1,width G1)`2 <= s } by A37,A41,A42; hence thesis by A26,A43,GOBRD11:25; suppose A44: j1 < width G1; then A45: 1 <= j1+1 & j1+1 <= width G1 & 1 <= j2+1 & j2+1 <= width G2 by A36,NAT_1:37,38; then A46: G1*(i1,j1+1) in Values G1 by A6,Lm1; G1*(i1,j1+1)`2 = G1*(1,j1+1)`2 & G2*(i2,j2+1)`2 = G2*(1,j2+1)`2 by A6,A7,A45,GOBOARD5:2; then G2*(1,j2+1)`2 <= G1*(1,j1+1)`2 by A1,A4,A6,A7,A36,A44,A46,Th16; then s' <= G1*(1,j1+1)`2 by A40,AXIOMS:22; then p in {|[r,s]|: r <= G1*(1,1)`1 & G1*(1,j1)`2 <= s & s <= G1*(1,j1+1)`2} by A37,A41,A42; hence thesis by A6,A26,A44,GOBRD11:26; end; hence thesis; end; hence thesis; suppose 1 < i1 & i2 = 1; hence thesis by A1,A2,A4,A7,Th10; suppose A47: 1 < i1 & 1 < i2; then A48: 1 <= i1-'1 & 1 <= i2-'1 by JORDAN3:12; then i1-'1 < i1 & i2-'1 < i2 by JORDAN3:14; then A49: i1-'1 < len G1 & i2-'1 < len G2 by A6,A7,AXIOMS:22; A50: i1-'1+1 = i1 & i2-'1+1 = i2 by A48,JORDAN3:6; A51: G1*(i1-'1,j1) in Values G1 by A6,A48,A49,Lm1; G1*(i1-'1,1)`1 = G1*(i1-'1,j1)`1 & G2*(i2-'1,1)`1 = G2*(i2-'1,j2)`1 by A6,A7,A48,A49,GOBOARD5:3; then A52: G1*(i1-'1,1)`1 <= G2*(i2-'1,1)`1 by A1,A4,A6,A7,A47,A51,Th15; now per cases by A7,REAL_1:def 5; suppose A53: j2 = width G2; then p in { |[r,s]|: G2*(i2-'1,1)`1 <= r & r <= G2*(i2,1)`1 & G2*(1,j2)`2 <= s} by A5,A48,A49,A50,GOBRD11:31; then consider r',s' such that A54: p = |[r',s']| and A55: G2*(i2-'1,1)`1 <= r' and A56: r' <= G2*(i2,1)`1 and A57: G2*(1,j2)`2 <= s'; A58: j1 = width G1 by A1,A2,A4,A7,A53,Th13; A59: G1*(i1-'1,1)`1 <= r' by A52,A55,AXIOMS:22; A60: r' <= G1*(i1,1)`1 by A4,A6,A8,A56,GOBOARD5:3; G1*(1,j1)`2 <= s' by A4,A6,A8,A57,GOBOARD5:2; then p in { |[r,s]|: G1*(i1-'1,1)`1 <= r & r <= G1*(i1,1)`1 & G1*(1,j1)`2 <= s} by A54,A59,A60; hence thesis by A48,A49,A50,A58,GOBRD11:31; suppose A61: j2 < width G2; then p in { |[r,s]| : G2*(i2-'1,1)`1 <= r & r <= G2*(i2,1)`1 & G2*(1,j2)`2 <= s & s <= G2*(1,j2+1)`2 } by A5,A7,A48,A49,A50,GOBRD11:32; then consider r',s' such that A62: p = |[r',s']| and A63: G2*(i2-'1,1)`1 <= r' and A64: r' <= G2*(i2,1)`1 and A65: G2*(1,j2)`2 <= s' and A66: s' <= G2*(1,j2+1)`2; A67: G1*(i1-'1,1)`1 <= r' by A52,A63,AXIOMS:22; A68: r' <= G1*(i1,1)`1 by A4,A6,A8,A64,GOBOARD5:3; A69: G1*(1,j1)`2 <= s' by A4,A6,A8,A65,GOBOARD5:2; now per cases by A6,REAL_1:def 5; suppose A70: j1 = width G1; p in { |[r,s]|: G1*(i1-'1,1)`1 <= r & r <= G1*(i1,1)`1 & G1*(1,j1)`2 <= s } by A62,A67,A68,A69; hence thesis by A48,A49,A50,A70,GOBRD11:31; suppose A71: j1 < width G1; then A72: 1 <= j1+1 & j1+1 <= width G1 & 1 <= j2+1 & j2+1 <= width G2 by A61,NAT_1:37,38; then A73: G1*(i1,j1+1) in Values G1 by A6,Lm1; G1*(i1,j1+1)`2 = G1*(1,j1+1)`2 & G2*(i2,j2+1)`2 = G2*(1,j2+1)`2 by A6,A7,A72,GOBOARD5:2; then G2*(1,j2+1)`2 <= G1*(1,j1+1)`2 by A1,A4,A6,A7,A61,A71,A73,Th16; then s' <= G1*(1,j1+1)`2 by A66,AXIOMS:22; then p in { |[r,s]| : G1*(i1-'1,1)`1 <= r & r <= G1*(i1,1)`1 & G1*(1,j1)`2 <= s & s <= G1*(1,j1+1)`2 } by A62,A67,A68,A69; hence thesis by A6,A48,A49,A50,A71,GOBRD11:32; end; hence thesis; end; hence thesis; end; theorem Th20: for G1,G2 being Go-board st Values G1 c= Values G2 & [i1,j1] in Indices G1 & [i2,j2] in Indices G2 & G1*(i1,j1) = G2*(i2,j2) holds cell(G2,i2,j2-'1) c= cell(G1,i1,j1-'1) proof let G1,G2 be Go-board such that A1: Values G1 c= Values G2 and A2: [i1,j1] in Indices G1 and A3: [i2,j2] in Indices G2 and A4: G1*(i1,j1) = G2*(i2,j2); let p be set such that A5: p in cell(G2,i2,j2-'1); A6: 1 <= i1 & i1 <= len G1 & 1 <= j1 & j1 <= width G1 by A2,GOBOARD5:1; A7: 1 <= i2 & i2 <= len G2 & 1 <= j2 & j2 <= width G2 by A3,GOBOARD5:1; A8: G1*(i1,j1)`1 = G1*(i1,1)`1 & G1*(i1,j1)`2 = G1*(1,j1)`2 by A6,GOBOARD5:2,3; A9: G2*(i2,j2)`1 = G2*(i2,1)`1 & G2*(i2,j2)`2 = G2*(1,j2)`2 by A7,GOBOARD5:2,3; per cases by A6,A7,REAL_1:def 5; suppose A10: j1 = 1 & j2 = 1; then A11: j1-'1 = 0 & j2-'1 = 0 by GOBOARD9:1; now per cases by A7,REAL_1:def 5; suppose A12: i2 = len G2; then p in { |[r,s]| : G2*(len G2,1)`1 <= r & s <= G2*(1,1)`2 } by A5,A11,GOBRD11:27; then consider r',s' such that A13: p = |[r',s']| and A14: G2*(len G2,1)`1 <= r' and A15: s' <= G2*(1,1)`2; A16: i1 = len G1 by A1,A2,A4,A7,A12,Th11; G2*(1,1)`2 = G2*(i2,j2)`2 by A7,A10,GOBOARD5:2; then s' <= G1*(1,1)`2 by A4,A6,A10,A15,GOBOARD5:2; then p in { |[r,s]| : G1*(len G1,1)`1 <= r & s <= G1*(1,1)`2 } by A4,A10,A12,A13,A14,A16; hence thesis by A11,A16,GOBRD11:27; suppose A17: i2 < len G2; then p in {|[r,s]|: G2*(i2,1)`1 <= r & r <= G2*(i2+1,1)`1 & s <= G2*(1,1)`2 } by A5,A7,A11,GOBRD11:30; then consider r',s' such that A18: p = |[r',s']| and A19: G2*(i2,1)`1 <= r' and A20: r' <= G2*(i2+1,1)`1 and A21: s' <= G2*(1,1)`2; G2*(1,1)`2 = G2*(i2,j1)`2 by A7,A10,GOBOARD5:2; then A22: s' <= G1*(1,1)`2 by A4,A6,A10,A21,GOBOARD5:2; now per cases by A6,REAL_1:def 5; suppose A23: i1 = len G1; then p in { |[r,s]| : G1*(len G1,1)`1 <= r & s <= G1*(1,1)`2 } by A4,A10,A18,A19,A22; hence thesis by A11,A23,GOBRD11:27; suppose A24: i1 < len G1; then G2*(i2+1,1)`1 <= G1*(i1+1,1)`1 by A1,A4,A6,A7,A10,A17,Th14; then r' <= G1*(i1+1,1)`1 by A20,AXIOMS:22; then p in {|[r,s]|: G1*(i1,1)`1 <= r & r <= G1*(i1+1,1)`1 & s <= G1*(1,1)`2} by A4,A10,A18,A19,A22; hence thesis by A6,A11,A24,GOBRD11:30; end; hence thesis; end; hence thesis; suppose that A25: j1 = 1 and A26: 1 < j2; A27: j1-'1 = 0 by A25,GOBOARD9:1; A28: 1 <= j2-'1 by A26,JORDAN3:12; then j2-'1 < j2 by JORDAN3:14; then A29: j2-'1 < width G2 by A7,AXIOMS:22; A30: j2-'1+1 = j2 by A26,AMI_5:4; now per cases by A7,REAL_1:def 5; suppose A31: i2 = len G2; then A32: i1 = len G1 by A1,A2,A4,A7,Th11; p in { |[r,s]| : G2*(i2,1)`1 <= r & G2*(1,j2-'1)`2 <= s & s <= G2*(1,j2)`2 } by A5,A28,A29,A30,A31,GOBRD11:29; then ex r',s' st p = |[r',s']| & G2*(i2,1)`1 <= r' & G2*(1,j2-'1)`2 <= s' & s' <= G2*(1,j2)`2; then p in { |[r,s]| : G1*(i1,1)`1 <= r & s <= G1*(1,1)`2 } by A4,A8,A9,A25; hence thesis by A27,A32,GOBRD11:27; suppose A33: i2 < len G2; then p in { |[r,s]| : G2*(i2,1)`1 <= r & r <= G2*(i2+1,1)`1 & G2*(1,j2-'1)`2 <= s & s <= G2*(1,j2)`2 } by A5,A7,A28,A29,A30,GOBRD11:32; then consider r',s' such that A34: p = |[r',s']| and A35: G2*(i2,1)`1 <= r' and A36: r' <= G2*(i2+1,1)`1 and G2*(1,j2-'1)`2 <= s' and A37: s' <= G2*(1,j2)`2; A38: s' <= G1*(1,1)`2 by A4,A7,A8,A25,A37,GOBOARD5:2; A39: G1*(i1,1)`1 <= r' by A4,A7,A8,A35,GOBOARD5:3; now per cases by A6,REAL_1:def 5; suppose A40: i1 = len G1; then p in { |[r,s]| : G1*(len G1,1)`1 <= r & s <= G1*(1,1)`2 } by A34,A38,A39; hence thesis by A27,A40,GOBRD11:27; suppose A41: i1 < len G1; then 1 <= i1+1 & i1+1 <= len G1 & 1 <= i2+1 & i2+1 <= len G2 by A33,NAT_1:37,38; then G1*(i1+1,j1)`1 = G1*(i1+1,1)`1 & G2*(i2+1,j2)`1 = G2*(i2+1,1)`1 by A6,A7,GOBOARD5:3; then G2*(i2+1,1)`1 <= G1*(i1+1,1)`1 by A1,A4,A6,A7,A33,A41,Th14; then r' <= G1*(i1+1,1)`1 by A36,AXIOMS:22; then p in {|[r,s]|: G1*(i1,1)`1 <= r & r <= G1*(i1+1,1)`1 & s <= G1*(1,1)`2} by A34,A38,A39; hence thesis by A6,A27,A41,GOBRD11:30; end; hence thesis; end; hence thesis; suppose 1 < j1 & j2 = 1; hence thesis by A1,A2,A4,A7,Th12; suppose A42: 1 < j1 & 1 < j2; then A43: 1 <= j1-'1 & 1 <= j2-'1 by JORDAN3:12; then j1-'1 < j1 & j2-'1 < j2 by JORDAN3:14; then A44: j1-'1 < width G1 & j2-'1 < width G2 by A6,A7,AXIOMS:22; A45: j1-'1+1 = j1 & j2-'1+1 = j2 by A43,JORDAN3:6; G1*(1,j1-'1)`2 = G1*(i1,j1-'1)`2 & G2*(1,j2-'1)`2 = G2*(i2,j2-'1)`2 by A6,A7,A43,A44,GOBOARD5:2; then A46: G1*(1,j1-'1)`2 <= G2*(1,j2-'1)`2 by A1,A4,A6,A7,A42,Th17; now per cases by A7,REAL_1:def 5; suppose A47: i2 = len G2; then p in { |[r,s]| : G2*(i2,1)`1 <= r & G2*(1,j2-'1)`2 <= s & s <= G2* (1,j2)`2} by A5,A43,A44,A45,GOBRD11:29; then consider r',s' such that A48: p = |[r',s']| and A49: G2*(i2,1)`1 <= r' and A50: G2*(1,j2-'1)`2 <= s' and A51: s' <= G2*(1,j2)`2; A52: i1 = len G1 by A1,A2,A4,A7,A47,Th11; A53: G1*(1,j1-'1)`2 <= s' by A46,A50,AXIOMS:22; A54: s' <= G1*(1,j1)`2 by A4,A6,A9,A51,GOBOARD5:2; G1*(i1,1)`1 <= r' by A4,A6,A9,A49,GOBOARD5:3; then p in {|[r,s]|: G1*(i1,1)`1 <= r & G1*(1,j1-'1)`2 <= s & s <= G1*(1,j1)`2} by A48,A53,A54; hence thesis by A43,A44,A45,A52,GOBRD11:29; suppose A55: i2 < len G2; then p in { |[r,s]| : G2*(i2,1)`1 <= r & r <= G2*(i2+1,1)`1 & G2*(1,j2-'1)`2 <= s & s <= G2*(1,j2)`2 } by A5,A7,A43,A44,A45,GOBRD11:32; then consider r',s' such that A56: p = |[r',s']| and A57: G2*(i2,1)`1 <= r' and A58: r' <= G2*(i2+1,1)`1 and A59: G2*(1,j2-'1)`2 <= s' and A60: s' <= G2*(1,j2)`2; A61: G1*(1,j1-'1)`2 <= s' by A46,A59,AXIOMS:22; A62: s' <= G1*(1,j1)`2 by A4,A6,A9,A60,GOBOARD5:2; A63: G1*(i1,1)`1 <= r' by A4,A6,A9,A57,GOBOARD5:3; now per cases by A6,REAL_1:def 5; suppose A64: i1 = len G1; p in {|[r,s]|: G1*(i1,1)`1 <= r & G1*(1,j1-'1)`2 <= s & s <= G1* (1,j1)`2} by A56,A61,A62,A63; hence thesis by A43,A44,A45,A64,GOBRD11:29; suppose A65: i1 < len G1; then 1 <= i1+1 & i1+1 <= len G1 & 1 <= i2+1 & i2+1 <= len G2 by A55,NAT_1:37,38; then G1*(i1+1,j1)`1 = G1*(i1+1,1)`1 & G2*(i2+1,j2)`1 = G2*(i2+1,1)`1 by A6,A7,GOBOARD5:3; then G2*(i2+1,1)`1 <= G1*(i1+1,1)`1 by A1,A4,A6,A7,A55,A65,Th14; then r' <= G1*(i1+1,1)`1 by A58,AXIOMS:22; then p in { |[r,s]| : G1*(i1,1)`1 <= r & r <= G1*(i1+1,1)`1 & G1*(1,j1-'1)`2 <= s & s <= G1*(1,j1)`2 } by A56,A61,A62,A63; hence thesis by A6,A43,A44,A45,A65,GOBRD11:32; end; hence thesis; end; hence thesis; end; Lm2: for f being non empty FinSequence of TOP-REAL 2 st 1 <= i & i <= len GoB f & 1 <= j & j <= width GoB f ex k st k in dom f & (f/.k)`1 = (GoB f)*(i,j)`1 proof let f be non empty FinSequence of TOP-REAL 2; assume A1: 1 <= i & i <= len GoB f & 1 <= j & j <= width GoB f; then A2: [i,j] in Indices GoB f by GOBOARD7:10; A3: GoB f = GoB (Incr X_axis f,Incr Y_axis f) by GOBOARD2:def 3; then len Incr X_axis f = len GoB f by GOBOARD2:def 1; then i in dom Incr X_axis f by A1,FINSEQ_3:27; then (Incr X_axis f).i in rng Incr X_axis f by FUNCT_1:def 5; then (Incr X_axis f).i in rng X_axis f by GOBOARD2:def 2; then consider k such that A4: k in dom X_axis f and A5: (X_axis f).k = (Incr X_axis f).i by FINSEQ_2:11; take k; len X_axis f = len f by GOBOARD1:def 3; hence k in dom f by A4,FINSEQ_3:31; A6: (GoB f)*(i,j) = |[Incr(X_axis f).i,Incr(Y_axis f).j]| by A2,A3,GOBOARD2:def 1; thus (f/.k)`1 = Incr(X_axis f).i by A4,A5,GOBOARD1:def 3 .= (GoB f)*(i,j)`1 by A6,EUCLID:56; end; Lm3: for f being non empty FinSequence of TOP-REAL 2 st 1 <= i & i <= len GoB f & 1 <= j & j <= width GoB f ex k st k in dom f & (f/.k)`2 = (GoB f)*(i,j)`2 proof let f be non empty FinSequence of TOP-REAL 2; assume A1: 1 <= i & i <= len GoB f & 1 <= j & j <= width GoB f; then A2: [i,j] in Indices GoB f by GOBOARD7:10; A3: GoB f = GoB (Incr X_axis f,Incr Y_axis f) by GOBOARD2:def 3; then len Incr Y_axis f = width GoB f by GOBOARD2:def 1; then j in dom Incr Y_axis f by A1,FINSEQ_3:27; then (Incr Y_axis f).j in rng Incr Y_axis f by FUNCT_1:def 5; then (Incr Y_axis f).j in rng Y_axis f by GOBOARD2:def 2; then consider k such that A4: k in dom Y_axis f and A5: (Y_axis f).k = (Incr Y_axis f).j by FINSEQ_2:11; take k; len Y_axis f = len f by GOBOARD1:def 4; hence k in dom f by A4,FINSEQ_3:31; A6: (GoB f)*(i,j) = |[Incr(X_axis f).i,Incr(Y_axis f).j]| by A2,A3,GOBOARD2:def 1; thus (f/.k)`2 = Incr(Y_axis f).j by A4,A5,GOBOARD1:def 4 .= (GoB f)*(i,j)`2 by A6,EUCLID:56; end; theorem Th21: for f being standard special_circular_sequence st f is_sequence_on G holds Values GoB f c= Values G proof let f be standard special_circular_sequence such that A1: f is_sequence_on G; set F = GoB f; let p be set; assume p in Values F; then p in { F*(i,j): [i,j] in Indices F } by Th7; then consider i,j such that A2: p = F*(i,j) and A3: [i,j] in Indices F; A4: 1 <= i & i <= len F & 1 <= j & j <= width F by A3,GOBOARD5:1; reconsider p as Point of TOP-REAL 2 by A2; consider k1 such that A5: k1 in dom f and A6: p`1 = (f/.k1)`1 by A2,A4,Lm2; consider k2 such that A7: k2 in dom f and A8: p`2 = (f/.k2)`2 by A2,A4,Lm3; consider i1,j1 such that A9: [i1,j1] in Indices G and A10: f/.k1 = G*(i1,j1) by A1,A5,GOBOARD1:def 11; A11: 1 <= i1 & i1 <= len G & 1 <= j1 & j1 <= width G by A9,GOBOARD5:1; consider i2,j2 such that A12: [i2,j2] in Indices G and A13: f/.k2 = G*(i2,j2) by A1,A7,GOBOARD1:def 11; A14: 1 <= i2 & i2 <= len G & 1 <= j2 & j2 <= width G by A12,GOBOARD5:1; then A15: G*(i1,j2)`1 = G*(i1,1)`1 by A11,GOBOARD5:3 .= G*(i1,j1)`1 by A11,GOBOARD5:3; A16: G*(i1,j2)`2 = G*(1,j2)`2 by A11,A14,GOBOARD5:2 .= G*(i2,j2)`2 by A14,GOBOARD5:2; A17: [i1,j2] in Indices G by A11,A14,GOBOARD7:10; p = |[p`1, p`2]| by EUCLID:57; then p = G*(i1,j2) by A6,A8,A10,A13,A15,A16,EUCLID:57; then p in { G*(k,l): [k,l] in Indices G } by A17; hence thesis by Th7; end; definition let f, G, k; assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G; consider i1,j1,i2,j2 being Nat such that A3: [i1,j1] in Indices G & f/.k = G*(i1,j1) and A4: [i2,j2] in Indices G & f/.(k+1) = G*(i2,j2) and A5: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,A2,JORDAN8:6; func right_cell(f,k,G) -> Subset of TOP-REAL 2 means :Def2: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & it = cell(G,i1,j1) or i1+1 = i2 & j1 = j2 & it = cell(G,i1,j1-'1) or i1 = i2+1 & j1 = j2 & it = cell(G,i2,j2) or i1 = i2 & j1 = j2+1 & it = cell(G,i1-'1,j2); existence proof per cases by A5; suppose A6: i1 = i2 & j1+1 = j2; take cell(G,i1,j1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A6; suppose A7: i1+1 = i2 & j1 = j2; take cell(G,i1,j1-'1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A7; suppose A8: i1 = i2+1 & j1 = j2; take cell(G,i2,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A8; suppose A9: i1 = i2 & j1 = j2+1; take cell(G,i1-'1,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A9; end; uniqueness proof let P1,P2 be Subset of TOP-REAL 2 such that A10: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P1 = cell(G,i1,j1) or i1+1 = i2 & j1 = j2 & P1 = cell(G,i1,j1-'1) or i1 = i2+1 & j1 = j2 & P1 = cell(G,i2,j2) or i1 = i2 & j1 = j2+1 & P1 = cell(G,i1-'1,j2) and A11: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P2 = cell(G,i1,j1) or i1+1 = i2 & j1 = j2 & P2 = cell(G,i1,j1-'1) or i1 = i2+1 & j1 = j2 & P2 = cell(G,i2,j2) or i1 = i2 & j1 = j2+1 & P2 = cell(G,i1-'1,j2); per cases by A5; suppose i1 = i2 & j1+1 = j2; then A12: j1 < j2 by REAL_1:69; A13: j2 <= j2+1 by NAT_1:29; hence P1 = cell(G,i1,j1) by A3,A4,A10,A12 .= P2 by A3,A4,A11,A12,A13; suppose i1+1 = i2 & j1 = j2; then A14: i1 < i2 by REAL_1:69; A15: i2 <= i2+1 by NAT_1:29; hence P1 = cell(G,i1,j1-'1) by A3,A4,A10,A14 .= P2 by A3,A4,A11,A14,A15; suppose i1 = i2+1 & j1 = j2; then A16: i2 < i1 by REAL_1:69; A17: i1 <= i1+1 by NAT_1:29; hence P1 = cell(G,i2,j2) by A3,A4,A10,A16 .= P2 by A3,A4,A11,A16,A17; suppose i1 = i2 & j1 = j2+1; then A18: j2 < j1 by REAL_1:69; A19: j1 <= j1+1 by NAT_1:29; hence P1 = cell(G,i1-'1,j2) by A3,A4,A10,A18 .= P2 by A3,A4,A11,A18,A19; end; func left_cell(f,k,G) -> Subset of TOP-REAL 2 means :Def3: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & it = cell(G,i1-'1,j1) or i1+1 = i2 & j1 = j2 & it = cell(G,i1,j1) or i1 = i2+1 & j1 = j2 & it = cell(G,i2,j2-'1) or i1 = i2 & j1 = j2+1 & it = cell(G,i1,j2); existence proof per cases by A5; suppose A20: i1 = i2 & j1+1 = j2; take cell(G,i1-'1,j1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A20; suppose A21: i1+1 = i2 & j1 = j2; take cell(G,i1,j1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A21; suppose A22: i1 = i2+1 & j1 = j2; take cell(G,i2,j2-'1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A22; suppose A23: i1 = i2 & j1 = j2+1; take cell(G,i1,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A23; end; uniqueness proof let P1,P2 be Subset of TOP-REAL 2 such that A24: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P1 = cell(G,i1-'1,j1) or i1+1 = i2 & j1 = j2 & P1 = cell(G,i1,j1) or i1 = i2+1 & j1 = j2 & P1 = cell(G,i2,j2-'1) or i1 = i2 & j1 = j2+1 & P1 = cell(G,i1,j2) and A25: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P2 = cell(G,i1-'1,j1) or i1+1 = i2 & j1 = j2 & P2 = cell(G,i1,j1) or i1 = i2+1 & j1 = j2 & P2 = cell(G,i2,j2-'1) or i1 = i2 & j1 = j2+1 & P2 = cell(G,i1,j2); per cases by A5; suppose i1 = i2 & j1+1 = j2; then A26: j1 < j2 by REAL_1:69; A27: j2 <= j2+1 by NAT_1:29; hence P1 = cell(G,i1-'1,j1) by A3,A4,A24,A26 .= P2 by A3,A4,A25,A26,A27; suppose i1+1 = i2 & j1 = j2; then A28: i1 < i2 by REAL_1:69; A29: i2 <= i2+1 by NAT_1:29; hence P1 = cell(G,i1,j1) by A3,A4,A24,A28 .= P2 by A3,A4,A25,A28,A29; suppose i1 = i2+1 & j1 = j2; then A30: i2 < i1 by REAL_1:69; A31: i1 <= i1+1 by NAT_1:29; hence P1 = cell(G,i2,j2-'1) by A3,A4,A24,A30 .= P2 by A3,A4,A25,A30,A31; suppose i1 = i2 & j1 = j2+1; then A32: j2 < j1 by REAL_1:69; A33: j1 <= j1+1 by NAT_1:29; hence P1 = cell(G,i1,j2) by A3,A4,A24,A32 .= P2 by A3,A4,A25,A32,A33; end; end; theorem Th22: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i,j+1] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i,j+1) implies left_cell(f,k,G) = cell(G,i-'1,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i,j+1] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i,j+1); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence left_cell(f,k,G) = cell(G,i-'1,j) by A1,A2,A3,A4,A5,A6,Def3; end; theorem Th23: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i,j+1] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i,j+1) implies right_cell(f,k,G) = cell(G,i,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i,j+1] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i,j+1); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence right_cell(f,k,G) = cell(G,i,j) by A1,A2,A3,A4,A5,A6,Def2; end; theorem Th24: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i+1,j) implies left_cell(f,k,G) = cell(G,i,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i+1,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence left_cell(f,k,G) = cell(G,i,j) by A1,A2,A3,A4,A5,A6,Def3; end; theorem Th25: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i+1,j) implies right_cell(f,k,G) = cell(G,i,j-'1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i+1,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence right_cell(f,k,G) = cell(G,i,j-'1) by A1,A2,A3,A4,A5,A6,Def2; end; theorem Th26: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i+1,j) & f/.(k+1) = G*(i,j) implies left_cell(f,k,G) = cell(G,i,j-'1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i+1,j) and A5: f/.(k+1) = G*(i,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence left_cell(f,k,G) = cell(G,i,j-'1) by A1,A2,A3,A4,A5,A6,Def3; end; theorem Th27: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i+1,j) & f/.(k+1) = G*(i,j) implies right_cell(f,k,G) = cell(G,i,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i+1,j) and A5: f/.(k+1) = G*(i,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence right_cell(f,k,G) = cell(G,i,j) by A1,A2,A3,A4,A5,A6,Def2; end; theorem Th28: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j+1] in Indices G & [i,j] in Indices G & f/.k = G*(i,j+1) & f/.(k+1) = G*(i,j) implies left_cell(f,k,G) = cell(G,i,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j+1] in Indices G & [i,j] in Indices G and A4: f/.k = G*(i,j+1) and A5: f/.(k+1) = G*(i,j); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence left_cell(f,k,G) = cell(G,i,j) by A1,A2,A3,A4,A5,A6,Def3; end; theorem Th29: 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j+1] in Indices G & [i,j] in Indices G & f/.k = G*(i,j+1) & f/.(k+1) = G*(i,j) implies right_cell(f,k,G) = cell(G,i-'1,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j+1] in Indices G & [i,j] in Indices G and A4: f/.k = G*(i,j+1) and A5: f/.(k+1) = G*(i,j); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence right_cell(f,k,G) = cell(G,i-'1,j) by A1,A2,A3,A4,A5,A6,Def2; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G implies left_cell(f,k,G) /\ right_cell(f,k,G) = LSeg(f,k) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G; k <= k+1 by NAT_1:29; then k <= len f by A1,AXIOMS:22; then A3: k in dom f by A1,FINSEQ_3:27; then consider i1,j1 being Nat such that A4: [i1,j1] in Indices G & f/.k = G*(i1,j1) by A2,GOBOARD1:def 11; k+1 >= 1 by NAT_1:29; then A5: k+1 in dom f by A1,FINSEQ_3:27; then consider i2,j2 being Nat such that A6: [i2,j2] in Indices G & f/.(k+1) = G*(i2,j2) by A2,GOBOARD1:def 11; A7: abs(i1-i2)+abs(j1-j2) = 1 by A2,A3,A4,A5,A6,GOBOARD1:def 11; A8: now per cases by A7,GOBOARD1:2; case that A9: abs(i1-i2) = 1 and A10: j1 = j2; A11: -(i1-i2) = i2-i1 by XCMPLX_1:143; i1-i2 >= 0 or i1-i2 < 0; then i1-i2 = 1 or -(i1-i2) = 1 by A9,ABSVALUE:def 1; hence i1 = i2+1 or i1+1 = i2 by A11,XCMPLX_1:27; thus j1 = j2 by A10; case that A12: i1 = i2 and A13: abs(j1-j2) = 1; A14: -(j1-j2) = j2-j1 by XCMPLX_1:143; j1-j2 >= 0 or j1-j2 < 0; then j1-j2 = 1 or -(j1-j2) = 1 by A13,ABSVALUE:def 1; hence j1 = j2+1 or j1+1 = j2 by A14,XCMPLX_1:27; thus i1 = i2 by A12; end; A15: 0+1 <= j1 & j1 <= width G by A4,GOBOARD5:1; A16: 1 <= j2 & j2 <= width G by A6,GOBOARD5:1; A17: 0+1 <= i1 & i1 <= len G by A4,GOBOARD5:1; A18: 1 <= i2 & i2 <= len G by A6,GOBOARD5:1; i1 > 0 by A17,NAT_1:38; then consider i such that A19: i+1 = i1 by NAT_1:22; A20: i < len G by A17,A19,NAT_1:38; j1 > 0 by A15,NAT_1:38; then consider j such that A21: j+1 = j1 by NAT_1:22; A22: j < width G by A15,A21,NAT_1:38; A23: i1-'1 = i & j1-'1=j by A19,A21,BINARITH:39; per cases by A8; suppose A24: i1 = i2 & j1+1 = j2; then A25: j1 < width G by A16,NAT_1:38; left_cell(f,k,G) = cell(G,i,j1) & right_cell(f,k,G) = cell(G,i1,j1) by A1,A2,A4,A6,A23,A24,Th22,Th23; hence left_cell(f,k,G) /\ right_cell(f,k,G) = LSeg(G*(i1,j1),G*(i1,j1+1)) by A15,A19,A20,A25,GOBOARD5:26 .= LSeg(f,k) by A1,A4,A6,A24,TOPREAL1:def 5; suppose A26: i1+1 = i2 & j1 = j2; then A27: i1 < len G by A18,NAT_1:38; left_cell(f,k,G) = cell(G,i1,j1) & right_cell(f,k,G) = cell(G,i1,j) by A1,A2,A4,A6,A23,A26,Th24,Th25; hence left_cell(f,k,G) /\ right_cell(f,k,G) = LSeg(G*(i1,j1),G*(i1+1,j1)) by A17,A21,A22,A27,GOBOARD5:27 .= LSeg(f,k) by A1,A4,A6,A26,TOPREAL1:def 5; suppose A28: i1 = i2+1 & j1 = j2; then A29: i2 < len G by A17,NAT_1:38; left_cell(f,k,G) = cell(G,i2,j) & right_cell(f,k,G) = cell(G,i2,j1) by A1,A2,A4,A6,A23,A28,Th26,Th27; hence left_cell(f,k,G) /\ right_cell(f,k,G) = LSeg(G*(i2+1,j1),G*(i2,j1)) by A18,A21,A22,A29,GOBOARD5:27 .= LSeg(f,k) by A1,A4,A6,A28,TOPREAL1:def 5; suppose A30: i1 = i2 & j1 = j2+1; then A31: j2 < width G by A15,NAT_1:38; left_cell(f,k,G) = cell(G,i1,j2) & right_cell(f,k,G) = cell(G,i,j2) by A1,A2,A4,A6,A23,A30,Th28,Th29; hence left_cell(f,k,G) /\ right_cell(f,k,G) = LSeg(G*(i1,j2+1),G*(i1,j2)) by A16,A19,A20,A31,GOBOARD5:26 .= LSeg(f,k) by A1,A4,A6,A30,TOPREAL1:def 5; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G implies right_cell(f,k,G) is closed proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G; consider i1,j1,i2,j2 being Nat such that A3: [i1,j1] in Indices G & f/.k = G*(i1,j1) and A4: [i2,j2] in Indices G & f/.(k+1) = G*(i2,j2) and A5: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,A2,JORDAN8:6; i1 = i2 & j1+1 = j2 & right_cell(f,k,G) = cell(G,i1,j1) or i1+1 = i2 & j1 = j2 & right_cell(f,k,G) = cell(G,i1,j1-'1) or i1 = i2+1 & j1 = j2 & right_cell(f,k,G) = cell(G,i2,j2) or i1 = i2 & j1 = j2+1 & right_cell(f,k,G) = cell(G,i1-'1,j2) by A1,A2,A3,A4,A5,Def2; hence thesis by GOBRD11:33; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & k+1 <= n implies left_cell(f,k,G) = left_cell(f|n,k,G) & right_cell(f,k,G) = right_cell(f|n,k,G) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: k+1 <= n; per cases; suppose len f <= n; hence thesis by TOPREAL1:2; suppose A4: n < len f; consider i1,j1,i2,j2 being Nat such that A5: [i1,j1] in Indices G & f/.k = G*(i1,j1) and A6: [i2,j2] in Indices G & f/.(k+1) = G*(i2,j2) and A7: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,A2,JORDAN8:6; A8: i1+1 > i1 & i2+1 > i2 & j1+1 > j1 & j2+1 > j2 by NAT_1:38; set lf = left_cell(f,k,G), lfn = left_cell(f|n,k,G), rf = right_cell(f,k,G), rfn = right_cell(f|n,k,G); A9: f|n is_sequence_on G by A2,GOBOARD1:38; A10: len(f|n) = n by A4,TOPREAL1:3; then k in dom(f|n) & k+1 in dom(f|n) by A1,A3,GOBOARD2:3; then A11: (f|n)/.k = f/.k & (f|n)/.(k+1) = f/.(k+1) by TOPREAL1:1; now per cases by A7; suppose A12: i1 = i2 & j1+1 = j2; hence lf = cell(G,i1-'1,j1) by A1,A2,A5,A6,A8,Def3 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A12,Def3; thus rf = cell(G,i1,j1) by A1,A2,A5,A6,A8,A12,Def2 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A12,Def2; suppose A13: i1+1 = i2 & j1 = j2; hence lf = cell(G,i1,j1) by A1,A2,A5,A6,A8,Def3 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A13,Def3; thus rf = cell(G,i1,j1-'1) by A1,A2,A5,A6,A8,A13,Def2 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A13,Def2; suppose A14: i1 = i2+1 & j1 = j2; hence lf = cell(G,i2,j2-'1) by A1,A2,A5,A6,A8,Def3 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A14,Def3; thus rf = cell(G,i2,j2) by A1,A2,A5,A6,A8,A14,Def2 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A14,Def2; suppose A15: i1 = i2 & j1 = j2+1; hence lf = cell(G,i1,j2) by A1,A2,A5,A6,A8,Def3 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A15,Def3; thus rf = cell(G,i1-'1,j2) by A1,A2,A5,A6,A8,A15,Def2 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A15,Def2; end; hence thesis; end; theorem 1 <= k & k+1 <= len(f/^n) & n <= len f & f is_sequence_on G implies left_cell(f,k+n,G) = left_cell(f/^n,k,G) & right_cell(f,k+n,G) = right_cell(f/^n,k,G) proof set g = (f/^n); assume that A1: 1 <= k & k+1 <= len g and A2: n <= len f and A3: f is_sequence_on G; A4: g is_sequence_on G by A3,JORDAN8:5; then consider i1,j1,i2,j2 being Nat such that A5: [i1,j1] in Indices G & g/.k = G*(i1,j1) and A6: [i2,j2] in Indices G & g/.(k+1) = G*(i2,j2) and A7: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,JORDAN8:6; A8: i1+1 > i1 & i2+1 > i2 & j1+1 > j1 & j2+1 > j2 by NAT_1:38; set lf = left_cell(f,k+n,G), lfn = left_cell(g,k,G), rf = right_cell(f,k+n,G), rfn = right_cell(g,k,G); A9: len g = len f - n by A2,RFINSEQ:def 2; k in dom g & k+1 in dom g by A1,GOBOARD2:3; then A10: g/.k = f/.(k+n) & g/.(k+1) = f/.(k+1+n) by FINSEQ_5:30; A11: k+1+n = k+n+1 by XCMPLX_1:1; k+1+n <= (len g)+n by A1,AXIOMS:24; then A12: 1 <= k+n & k+1+n <= len f by A1,A9,NAT_1:37,XCMPLX_1:27; now per cases by A7; suppose A13: i1 = i2 & j1+1 = j2; hence lf = cell(G,i1-'1,j1) by A3,A5,A6,A8,A10,A11,A12,Def3 .= lfn by A1,A4,A5,A6,A8,A13,Def3; thus rf = cell(G,i1,j1) by A3,A5,A6,A8,A10,A11,A12,A13,Def2 .= rfn by A1,A4,A5,A6,A8,A13,Def2; suppose A14: i1+1 = i2 & j1 = j2; hence lf = cell(G,i1,j1) by A3,A5,A6,A8,A10,A11,A12,Def3 .= lfn by A1,A4,A5,A6,A8,A14,Def3; thus rf = cell(G,i1,j1-'1) by A3,A5,A6,A8,A10,A11,A12,A14,Def2 .= rfn by A1,A4,A5,A6,A8,A14,Def2; suppose A15: i1 = i2+1 & j1 = j2; hence lf = cell(G,i2,j2-'1) by A3,A5,A6,A8,A10,A11,A12,Def3 .= lfn by A1,A4,A5,A6,A8,A15,Def3; thus rf = cell(G,i2,j2) by A3,A5,A6,A8,A10,A11,A12,A15,Def2 .= rfn by A1,A4,A5,A6,A8,A15,Def2; suppose A16: i1 = i2 & j1 = j2+1; hence lf = cell(G,i1,j2) by A3,A5,A6,A8,A10,A11,A12,Def3 .= lfn by A1,A4,A5,A6,A8,A16,Def3; thus rf = cell(G,i1-'1,j2) by A3,A5,A6,A8,A10,A11,A12,A16,Def2 .= rfn by A1,A4,A5,A6,A8,A16,Def2; end; hence thesis; end; theorem for G being Go-board, f being standard special_circular_sequence st 1 <= n & n+1 <= len f & f is_sequence_on G holds left_cell(f,n,G) c= left_cell(f,n) & right_cell(f,n,G) c= right_cell(f,n) proof let G be Go-board,f be standard special_circular_sequence such that A1: 1 <= n & n+1 <= len f and A2: f is_sequence_on G; set F = GoB f; A3: Values F c= Values G by A2,Th21; f is_sequence_on F by GOBOARD5:def 5; then consider m,k,i,j such that A4: [m,k] in Indices F and A5: f/.n = F*(m,k) and A6: [i,j] in Indices F and A7: f/.(n+1) = F*(i,j) and m = i & k+1 = j or m+1 = i & k = j or m = i+1 & k = j or m = i & k = j+1 by A1,JORDAN8:6; A8: 1 <= m & m <= len F & 1 <= k & k <= width F by A4,GOBOARD5:1; A9: 1 <= i & i <= len F & 1 <= j & j <= width F by A6,GOBOARD5:1; then A10: F*(i,j)`1 = F*(i,1)`1 & F*(i,k)`1 = F*(i,1)`1 by A8,GOBOARD5:3; A11: F*(i,j)`2 = F*(1,j)`2 & F*(m,j)`2 = F*(1,j)`2 by A8,A9,GOBOARD5:2; consider i1,j1,i2,j2 such that A12: [i1,j1] in Indices G and A13: f/.n = G*(i1,j1) and A14: [i2,j2] in Indices G and A15: f/.(n+1) = G*(i2,j2) and A16: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,A2,JORDAN8:6; A17: 1 <= i1 & i1 <= len G & 1 <= j1 & j1 <= width G by A12,GOBOARD5:1; A18: 1 <= i2 & i2 <= len G & 1 <= j2 & j2 <= width G by A14,GOBOARD5:1; then A19: G*(i1,j1)`1 = G*(i1,1)`1 & G*(i2,j2)`1 = G*(i2,1)`1 by A17,GOBOARD5: 3; A20: G*(i1,j1)`2 = G*(1,j1)`2 & G*(i2,j1)`2 = G*(1,j1)`2 by A17,A18,GOBOARD5:2 ; A21: k+1 >= 1 & j+1 >= 1 & m+1 >= 1 & i+1 >= 1 by NAT_1:37; A22: k+1 > k & j+1 > j & m+1 > m & i+1 > i by NAT_1:38; A23: i1+1 > i1 & j1+1 > j1 & i2+1 > i2 & j2+1 > j2 by NAT_1:38; per cases by A16; suppose A24: i1 = i2 & j1+1 = j2; now assume j <= k; then A25: F*(i,j)`2 <= F*(m,k)`2 by A8,A9,A11,SPRECT_3:24; j1 < j2 by A24,NAT_1:38; hence contradiction by A5,A7,A13,A15,A17,A18,A20,A25,GOBOARD5:5; end; then A26: k+1 <= j by NAT_1:38; now assume A27: k+1 < j; then A28: k+1 < width F by A9,AXIOMS:22; then consider l,i' such that A29: l in dom f and A30: [i',k+1] in Indices F and A31: f/.l = F*(i',k+1) by A21,JORDAN5D:10; 1 <= i' & i' <= len F by A30,GOBOARD5:1; then A32: F*(i',k+1)`2 = F*(1,k+1)`2 & F*(m,k+1)`2 = F*(1,k+1)`2 by A8,A21,A28,GOBOARD5:2; consider i1',j1' such that A33: [i1',j1'] in Indices G and A34: f/.l = G*(i1',j1') by A2,A29,GOBOARD1:def 11; A35: 1 <= i1' & i1' <= len G & 1 <= j1' & j1' <= width G by A33,GOBOARD5:1; then A36: G*(i1',j1')`2 = G*(1,j1')`2 & G*(i1',j1)`2 = G*(1,j1)`2 by A17,GOBOARD5:2; A37: G*(i2,j2)`2 = G*(1,j2)`2 & G*(i1',j2)`2 = G*(1,j2)`2 by A18,A35,GOBOARD5:2; A38: now assume j1 >= j1'; then G*(i1',j1')`2 <= G*(i1,j1)`2 by A17,A20,A35,A36,SPRECT_3:24; hence contradiction by A5,A8,A13,A22,A28,A31,A32,A34,GOBOARD5:5; end; now assume j2 <= j1'; then G*(i2,j2)`2 <= G*(i1',j1')`2 by A18,A35,A37,SPRECT_3:24; hence contradiction by A7,A8,A9,A11,A15,A21,A27,A31,A32,A34,GOBOARD5:5; end; hence contradiction by A24,A38,NAT_1:38; end; then A39: k+1 = j by A26,AXIOMS:21; then A40: right_cell(f,n,G) = cell(G,i1,j1) & right_cell(f,n) = cell(F,m,k) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A24,Def2,GOBOARD5:def 6; left_cell(f,n,G) = cell(G,i1-'1,j1) & left_cell(f,n) = cell(F,m-'1,k) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A24,A39,Def3,GOBOARD5:def 7; hence thesis by A3,A4,A5,A12,A13,A40,Th18,Th19; suppose A41: i1+1 = i2 & j1 = j2; now assume i <= m; then A42: F*(i,j)`1 <= F*(m,k)`1 by A8,A9,A10,SPRECT_3:25; i1 < i2 by A41,NAT_1:38; hence contradiction by A5,A7,A13,A15,A17,A18,A41,A42,GOBOARD5:4; end; then A43: m+1 <= i by NAT_1:38; now assume A44: m+1 < i; then A45: m+1 < len F by A9,AXIOMS:22; then consider l,j' such that A46: l in dom f and A47: [m+1,j'] in Indices F and A48: f/.l = F*(m+1,j') by A21,JORDAN5D:9; A49: 1 <= m+1 by NAT_1:37; 1 <= j' & j' <= width F by A47,GOBOARD5:1; then A50: F*(m+1,j')`1 = F*(m+1,1)`1 & F*(m+1,k)`1 = F*(m+1,1)`1 by A8,A21,A45,GOBOARD5:3; A51: F*(m+1,j)`1 = F*(m+1,1)`1 & F*(m+1,k)`1 = F*(m+1,1)`1 by A8,A9,A21,A45,GOBOARD5:3; consider i1',j1' such that A52: [i1',j1'] in Indices G and A53: f/.l = G*(i1',j1') by A2,A46,GOBOARD1:def 11; A54: 1 <= i1' & i1' <= len G & 1 <= j1' & j1' <= width G by A52,GOBOARD5:1; then A55: G*(i1',j1')`1 = G*(i1',1)`1 & G*(i1',j1)`1 = G*(i1',1)`1 by A17,GOBOARD5:3; A56: G*(i2,j2)`1 = G*(i2,1)`1 & G*(i2,j1')`1 = G*(i2,1)`1 by A18,A54,GOBOARD5:3; A57: now assume i1 >= i1'; then G*(i1',j1')`1 <= G*(i1,j1)`1 by A17,A54,A55,SPRECT_3:25; hence contradiction by A5,A8,A13,A22,A45,A48,A50,A53,GOBOARD5:4; end; now assume i2 <= i1'; then G*(i2,j2)`1 <= G*(i1',j1')`1 by A18,A54,A56,SPRECT_3:25; hence contradiction by A7,A9,A15,A44,A48,A49,A50,A51,A53,GOBOARD5:4; end; hence contradiction by A41,A57,NAT_1:38; end; then A58: m+1 = i by A43,AXIOMS:21; then A59: right_cell(f,n,G) = cell(G,i1,j1-'1) & right_cell(f,n) = cell(F,m, k-'1) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A41,Def2,GOBOARD5:def 6; left_cell(f,n,G) = cell(G,i1,j1) & left_cell(f,n) = cell(F,m,k) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A41,A58,Def3,GOBOARD5:def 7; hence thesis by A3,A4,A5,A12,A13,A59,Th18,Th20; suppose A60: i1 = i2+1 & j1 = j2; now assume m <= i; then A61: F*(i,j)`1 >= F*(m,k)`1 by A8,A9,A10,SPRECT_3:25; i1 > i2 by A60,NAT_1:38; hence contradiction by A5,A7,A13,A15,A17,A18,A60,A61,GOBOARD5:4; end; then A62: i+1 <= m by NAT_1:38; now assume A63: m > i+1; then A64: i+1 < len F by A8,AXIOMS:22; then consider l,j' such that A65: l in dom f and A66: [i+1,j'] in Indices F and A67: f/.l = F*(i+1,j') by A21,JORDAN5D:9; A68: 1 <= i+1 by NAT_1:37; 1 <= j' & j' <= width F by A66,GOBOARD5:1; then A69: F*(i+1,j')`1 = F*(i+1,1)`1 & F*(i+1,j)`1 = F*(i+1,1)`1 by A9,A21,A64,GOBOARD5:3; A70: F*(i+1,j)`1 = F*(i+1,1)`1 & F*(i+1,k)`1 = F*(i+1,1)`1 by A8,A9,A21,A64,GOBOARD5:3; consider i1',j1' such that A71: [i1',j1'] in Indices G and A72: f/.l = G*(i1',j1') by A2,A65,GOBOARD1:def 11; A73: 1 <= i1' & i1' <= len G & 1 <= j1' & j1' <= width G by A71,GOBOARD5:1; then A74: G*(i1',j1')`1 = G*(i1',1)`1 & G*(i1',j1)`1 = G*(i1',1)`1 by A17,GOBOARD5:3; A75: G*(i2,j2)`1 = G*(i2,1)`1 & G*(i2,j1')`1 = G*(i2,1)`1 by A18,A73,GOBOARD5:3; A76: now assume i2 >= i1'; then G*(i2,j2)`1 >= G*(i1',j1')`1 by A18,A73,A75,SPRECT_3:25; hence contradiction by A7,A9,A15,A22,A64,A67,A69,A72,GOBOARD5:4; end; now assume i1 <= i1'; then G*(i1',j1')`1 >= G*(i1,j1)`1 by A17,A73,A74,SPRECT_3:25; hence contradiction by A5,A8,A13,A63,A67,A68,A69,A70,A72,GOBOARD5:4; end; hence contradiction by A60,A76,NAT_1:38; end; then A77: i+1 = m by A62,AXIOMS:21; then A78: right_cell(f,n,G) = cell(G,i2,j2) & right_cell(f,n) = cell(F,i,j) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A60,Def2,GOBOARD5:def 6; left_cell(f,n,G) = cell(G,i2,j2-'1) & left_cell(f,n) = cell(F,i,j-'1) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A60,A77,Def3,GOBOARD5:def 7; hence thesis by A3,A6,A7,A14,A15,A78,Th18,Th20; suppose A79: i1 = i2 & j1 = j2+1; A80: now assume A81: m <> i; per cases by A81,REAL_1:def 5; suppose m < i; hence contradiction by A5,A7,A8,A9,A10,A13,A15,A19,A79,GOBOARD5:4; suppose m > i; hence contradiction by A5,A7,A8,A9,A10,A13,A15,A19,A79,GOBOARD5:4; end; now assume j >= k; then A82: F*(i,j)`2 >= F*(m,k)`2 by A8,A9,A11,SPRECT_3:24; j1 > j2 by A79,NAT_1:38; hence contradiction by A5,A7,A13,A15,A17,A18,A20,A82,GOBOARD5:5; end; then A83: j+1 <= k by NAT_1:38; now assume A84: j+1 < k; then A85: j+1 < width F by A8,AXIOMS:22; then consider l,i' such that A86: l in dom f and A87: [i',j+1] in Indices F and A88: f/.l = F*(i',j+1) by A21,JORDAN5D:10; 1 <= i' & i' <= len F by A87,GOBOARD5:1; then A89: F*(i',j+1)`2 = F*(1,j+1)`2 & F*(i,j+1)`2 = F*(1,j+1)`2 by A9,A21,A85,GOBOARD5:2; A90: F*(i,j+1)`2 = F*(1,j+1)`2 & F*(m,j+1)`2 = F*(1,j+1)`2 by A8,A9,A21,A85,GOBOARD5:2; consider i1',j1' such that A91: [i1',j1'] in Indices G and A92: f/.l = G*(i1',j1') by A2,A86,GOBOARD1:def 11; A93: 1 <= i1' & i1' <= len G & 1 <= j1' & j1' <= width G by A91,GOBOARD5:1; then A94: G*(i1',j1')`2 = G*(1,j1')`2 & G*(i1',j1)`2 = G*(1,j1)`2 by A17,GOBOARD5:2; A95: G*(i2,j2)`2 = G*(1,j2)`2 & G*(i1',j2)`2 = G*(1,j2)`2 by A18,A93,GOBOARD5:2; A96: now assume j2 >= j1'; then G*(i2,j2)`2 >= G*(i1',j1')`2 by A18,A93,A95,SPRECT_3:24; hence contradiction by A7,A9,A15,A22,A85,A88,A89,A92,GOBOARD5:5; end; now assume j1 <= j1'; then G*(i1',j1')`2 >= G*(i1,j1)`2 by A17,A20,A93,A94,SPRECT_3:24; hence contradiction by A5,A8,A13,A21,A84,A88,A89,A90,A92,GOBOARD5:5; end; hence contradiction by A79,A96,NAT_1:38; end; then A97: j+1 = k by A83,AXIOMS:21; then A98: right_cell(f,n,G) = cell(G,i1-'1,j2) & right_cell(f,n) = cell(F,m -'1,j) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A79,Def2,GOBOARD5:def 6; left_cell(f,n,G) = cell(G,i1,j2) & left_cell(f,n) = cell(F,m,j) by A1,A2,A4,A5,A6,A7,A12,A13,A14,A15,A22,A23,A79,A97,Def3,GOBOARD5:def 7; hence thesis by A3,A6,A7,A14,A15,A79,A80,A98,Th18,Th19; end; definition let f,G,k; assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G; consider i1,j1,i2,j2 being Nat such that A3: [i1,j1] in Indices G & f/.k = G*(i1,j1) and A4: [i2,j2] in Indices G & f/.(k+1) = G*(i2,j2) and A5: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,A2,JORDAN8:6; func front_right_cell(f,k,G) -> Subset of TOP-REAL 2 means :Def4: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & it = cell(G,i2,j2) or i1+1 = i2 & j1 = j2 & it = cell(G,i2,j2-'1) or i1 = i2+1 & j1 = j2 & it = cell(G,i2-'1,j2) or i1 = i2 & j1 = j2+1 & it = cell(G,i2-'1,j2-'1); existence proof per cases by A5; suppose A6: i1 = i2 & j1+1 = j2; take cell(G,i2,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A6; suppose A7: i1+1 = i2 & j1 = j2; take cell(G,i2,j2-'1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A7; suppose A8: i1 = i2+1 & j1 = j2; take cell(G,i2-'1,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A8; suppose A9: i1 = i2 & j1 = j2+1; take cell(G,i2-'1,j2-'1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A9; end; uniqueness proof let P1,P2 be Subset of TOP-REAL 2 such that A10: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P1 = cell(G,i2,j2) or i1+1 = i2 & j1 = j2 & P1 = cell(G,i2,j2-'1) or i1 = i2+1 & j1 = j2 & P1 = cell(G,i2-'1,j2) or i1 = i2 & j1 = j2+1 & P1 = cell(G,i2-'1,j2-'1) and A11: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P2 = cell(G,i2,j2) or i1+1 = i2 & j1 = j2 & P2 = cell(G,i2,j2-'1) or i1 = i2+1 & j1 = j2 & P2 = cell(G,i2-'1,j2) or i1 = i2 & j1 = j2+1 & P2 = cell(G,i2-'1,j2-'1); per cases by A5; suppose i1 = i2 & j1+1 = j2; then A12: j1 < j2 by REAL_1:69; A13: j2 <= j2+1 by NAT_1:29; hence P1 = cell(G,i2,j2) by A3,A4,A10,A12 .= P2 by A3,A4,A11,A12,A13; suppose i1+1 = i2 & j1 = j2; then A14: i1 < i2 by REAL_1:69; A15: i2 <= i2+1 by NAT_1:29; hence P1 = cell(G,i2,j2-'1) by A3,A4,A10,A14 .= P2 by A3,A4,A11,A14,A15; suppose i1 = i2+1 & j1 = j2; then A16: i2 < i1 by REAL_1:69; A17: i1 <= i1+1 by NAT_1:29; hence P1 = cell(G,i2-'1,j2) by A3,A4,A10,A16 .= P2 by A3,A4,A11,A16,A17; suppose i1 = i2 & j1 = j2+1; then A18: j2 < j1 by REAL_1:69; A19: j1 <= j1+1 by NAT_1:29; hence P1 = cell(G,i2-'1,j2-'1) by A3,A4,A10,A18 .= P2 by A3,A4,A11,A18,A19; end; func front_left_cell(f,k,G) -> Subset of TOP-REAL 2 means :Def5: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & it = cell(G,i2-'1,j2) or i1+1 = i2 & j1 = j2 & it = cell(G,i2,j2) or i1 = i2+1 & j1 = j2 & it = cell(G,i2-'1,j2-'1) or i1 = i2 & j1 = j2+1 & it = cell(G,i2,j2-'1); existence proof per cases by A5; suppose A20: i1 = i2 & j1+1 = j2; take cell(G,i2-'1,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A20; suppose A21: i1+1 = i2 & j1 = j2; take cell(G,i2,j2); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A21; suppose A22: i1 = i2+1 & j1 = j2; take cell(G,i2-'1,j2-'1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A22; suppose A23: i1 = i2 & j1 = j2+1; take cell(G,i2,j2-'1); let i1',j1',i2',j2' be Nat; assume [i1',j1'] in Indices G & [i2',j2'] in Indices G & f/.k = G*(i1',j1') & f/.(k+1) = G*(i2',j2'); then i1 = i1' & i2 = i2' & j1 = j1' & j2 = j2' by A3,A4,GOBOARD1:21; hence thesis by A23; end; uniqueness proof let P1,P2 be Subset of TOP-REAL 2 such that A24: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P1 = cell(G,i2-'1,j2) or i1+1 = i2 & j1 = j2 & P1 = cell(G,i2,j2) or i1 = i2+1 & j1 = j2 & P1 = cell(G,i2-'1,j2-'1) or i1 = i2 & j1 = j2+1 & P1 = cell(G,i2,j2-'1) and A25: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & P2 = cell(G,i2-'1,j2) or i1+1 = i2 & j1 = j2 & P2 = cell(G,i2,j2) or i1 = i2+1 & j1 = j2 & P2 = cell(G,i2-'1,j2-'1) or i1 = i2 & j1 = j2+1 & P2 = cell(G,i2,j2-'1); per cases by A5; suppose i1 = i2 & j1+1 = j2; then A26: j1 < j2 by REAL_1:69; A27: j2 <= j2+1 by NAT_1:29; hence P1 = cell(G,i2-'1,j2) by A3,A4,A24,A26 .= P2 by A3,A4,A25,A26,A27; suppose i1+1 = i2 & j1 = j2; then A28: i1 < i2 by REAL_1:69; A29: i2 <= i2+1 by NAT_1:29; hence P1 = cell(G,i2,j2) by A3,A4,A24,A28 .= P2 by A3,A4,A25,A28,A29; suppose i1 = i2+1 & j1 = j2; then A30: i2 < i1 by REAL_1:69; A31: i1 <= i1+1 by NAT_1:29; hence P1 = cell(G,i2-'1,j2-'1) by A3,A4,A24,A30 .= P2 by A3,A4,A25,A30,A31; suppose i1 = i2 & j1 = j2+1; then A32: j2 < j1 by REAL_1:69; A33: j1 <= j1+1 by NAT_1:29; hence P1 = cell(G,i2,j2-'1) by A3,A4,A24,A32 .= P2 by A3,A4,A25,A32,A33; end; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i,j+1] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i,j+1) implies front_left_cell(f,k,G) = cell(G,i-'1,j+1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i,j+1] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i,j+1); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence front_left_cell(f,k,G) = cell(G,i-'1,j+1) by A1,A2,A3,A4,A5,A6,Def5; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i,j+1] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i,j+1) implies front_right_cell(f,k,G) = cell(G,i,j+1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i,j+1] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i,j+1); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence front_right_cell(f,k,G) = cell(G,i,j+1) by A1,A2,A3,A4,A5,A6,Def4; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i+1,j) implies front_left_cell(f,k,G) = cell(G,i+1,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i+1,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence front_left_cell(f,k,G) = cell(G,i+1,j) by A1,A2,A3,A4,A5,A6,Def5; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i,j) & f/.(k+1) = G*(i+1,j) implies front_right_cell(f,k,G) = cell(G,i+1,j-'1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i,j) and A5: f/.(k+1) = G*(i+1,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence front_right_cell(f,k,G) = cell(G,i+1,j-'1) by A1,A2,A3,A4,A5,A6,Def4; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i+1,j) & f/.(k+1) = G*(i,j) implies front_left_cell(f,k,G) = cell(G,i-'1,j-'1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i+1,j) and A5: f/.(k+1) = G*(i,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence front_left_cell(f,k,G) = cell(G,i-'1,j-'1) by A1,A2,A3,A4,A5,A6,Def5; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j] in Indices G & [i+1,j] in Indices G & f/.k = G*(i+1,j) & f/.(k+1) = G*(i,j) implies front_right_cell(f,k,G) = cell(G,i-'1,j) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j] in Indices G & [i+1,j] in Indices G and A4: f/.k = G*(i+1,j) and A5: f/.(k+1) = G*(i,j); A6: i < i+1 by REAL_1:69; i+1 <= i+1+1 by NAT_1:29; hence front_right_cell(f,k,G) = cell(G,i-'1,j) by A1,A2,A3,A4,A5,A6,Def4; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j+1] in Indices G & [i,j] in Indices G & f/.k = G*(i,j+1) & f/.(k+1) = G*(i,j) implies front_left_cell(f,k,G) = cell(G,i,j-'1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j+1] in Indices G & [i,j] in Indices G and A4: f/.k = G*(i,j+1) and A5: f/.(k+1) = G*(i,j); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence front_left_cell(f,k,G) = cell(G,i,j-'1) by A1,A2,A3,A4,A5,A6,Def5; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & [i,j+1] in Indices G & [i,j] in Indices G & f/.k = G*(i,j+1) & f/.(k+1) = G*(i,j) implies front_right_cell(f,k,G) = cell(G,i-'1,j-'1) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: [i,j+1] in Indices G & [i,j] in Indices G and A4: f/.k = G*(i,j+1) and A5: f/.(k+1) = G*(i,j); A6: j < j+1 by REAL_1:69; j+1 <= j+1+1 by NAT_1:29; hence front_right_cell(f,k,G) = cell(G,i-'1,j-'1) by A1,A2,A3,A4,A5,A6,Def4 ; end; theorem 1 <= k & k+1 <= len f & f is_sequence_on G & k+1 <= n implies front_left_cell(f,k,G) = front_left_cell(f|n,k,G) & front_right_cell(f,k,G) = front_right_cell(f|n,k,G) proof assume that A1: 1 <= k & k+1 <= len f and A2: f is_sequence_on G and A3: k+1 <= n; per cases; suppose len f <= n; hence thesis by TOPREAL1:2; suppose A4: n < len f; consider i1,j1,i2,j2 being Nat such that A5: [i1,j1] in Indices G & f/.k = G*(i1,j1) and A6: [i2,j2] in Indices G & f/.(k+1) = G*(i2,j2) and A7: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A1,A2,JORDAN8:6; A8: i1+1 > i1 & i2+1 > i2 & j1+1 > j1 & j2+1 > j2 by NAT_1:38; set lf = front_left_cell(f,k,G), lfn = front_left_cell(f|n,k,G), rf = front_right_cell(f,k,G), rfn = front_right_cell(f|n,k,G); A9: f|n is_sequence_on G by A2,GOBOARD1:38; A10: len(f|n) = n by A4,TOPREAL1:3; then k in dom(f|n) & k+1 in dom(f|n) by A1,A3,GOBOARD2:3; then A11: (f|n)/.k = f/.k & (f|n)/.(k+1) = f/.(k+1) by TOPREAL1:1; now per cases by A7; suppose A12: i1 = i2 & j1+1 = j2; hence lf = cell(G,i2-'1,j2) by A1,A2,A5,A6,A8,Def5 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A12,Def5; thus rf = cell(G,i2,j2) by A1,A2,A5,A6,A8,A12,Def4 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A12,Def4; suppose A13: i1+1 = i2 & j1 = j2; hence lf = cell(G,i2,j2) by A1,A2,A5,A6,A8,Def5 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A13,Def5; thus rf = cell(G,i2,j2-'1) by A1,A2,A5,A6,A8,A13,Def4 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A13,Def4; suppose A14: i1 = i2+1 & j1 = j2; hence lf = cell(G,i2-'1,j2-'1) by A1,A2,A5,A6,A8,Def5 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A14,Def5; thus rf = cell(G,i2-'1,j2) by A1,A2,A5,A6,A8,A14,Def4 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A14,Def4; suppose A15: i1 = i2 & j1 = j2+1; hence lf = cell(G,i2,j2-'1) by A1,A2,A5,A6,A8,Def5 .= lfn by A1,A3,A5,A6,A8,A9,A10,A11,A15,Def5; thus rf = cell(G,i2-'1,j2-'1) by A1,A2,A5,A6,A8,A15,Def4 .= rfn by A1,A3,A5,A6,A8,A9,A10,A11,A15,Def4; end; hence thesis; end; definition let D be set; let f be FinSequence of D, G be (Matrix of D), k; pred f turns_right k,G means :Def6: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & [i2+1,j2] in Indices G & f/.(k+2) = G*(i2+1,j2) or i1+1 = i2 & j1 = j2 & [i2,j2-'1] in Indices G & f/.(k+2) = G* (i2,j2-'1) or i1 = i2+1 & j1 = j2 & [i2,j2+1] in Indices G & f/.(k+2) = G*(i2,j2+1) or i1 = i2 & j1 = j2+1 & [i2-'1,j2] in Indices G & f/.(k+2) = G*(i2-'1,j2); pred f turns_left k,G means :Def7: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & [i2-'1,j2] in Indices G & f/.(k+2) = G* (i2-'1,j2) or i1+1 = i2 & j1 = j2 & [i2,j2+1] in Indices G & f/.(k+2) = G*(i2,j2+1) or i1 = i2+1 & j1 = j2 & [i2,j2-'1] in Indices G & f/.(k+2) = G* (i2,j2-'1) or i1 = i2 & j1 = j2+1 & [i2+1,j2] in Indices G & f/.(k+2) = G*(i2+1,j2); pred f goes_straight k,G means :Def8: for i1,j1,i2,j2 being Nat st [i1,j1] in Indices G & [i2,j2] in Indices G & f/.k = G*(i1,j1) & f/.(k+1) = G*(i2,j2) holds i1 = i2 & j1+1 = j2 & [i2,j2+1] in Indices G & f/.(k+2) = G*(i2,j2+1) or i1+1 = i2 & j1 = j2 & [i2+1,j2] in Indices G & f/.(k+2) = G*(i2+1,j2) or i1 = i2+1 & j1 = j2 & [i2-'1,j2] in Indices G & f/.(k+2) = G* (i2-'1,j2) or i1 = i2 & j1 = j2+1 & [i2,j2-'1] in Indices G & f/.(k+2) = G*(i2,j2-'1); end; reserve D for set, f,f1,f2 for FinSequence of D, G for Matrix of D; theorem 1 <= k & k+2 <= len f & k+2 <= n & f|n turns_right k,G implies f turns_right k,G proof assume that A1: 1 <= k & k+2 <= len f and A2: k+2 <= n and A3: f|n turns_right k,G; per cases; suppose len f <= n; hence thesis by A3,TOPREAL1:2; suppose n < len f; then len(f|n) = n by TOPREAL1:3; then k in dom(f|n) & k+1 in dom(f|n) & k+2 in dom(f|n) by A1,A2,GOBOARD2:4; then A4: (f|n)/.k = f/.k & (f|n)/.(k+1) = f/.(k+1) & (f|n)/.(k+2) = f/.(k+2) by TOPREAL1:1; let i1',j1',i2',j2' be Nat; thus thesis by A3,A4,Def6; end; theorem 1 <= k & k+2 <= len f & k+2 <= n & f|n turns_left k,G implies f turns_left k,G proof assume that A1: 1 <= k & k+2 <= len f and A2: k+2 <= n and A3: f|n turns_left k,G; per cases; suppose len f <= n; hence thesis by A3,TOPREAL1:2; suppose n < len f; then len(f|n) = n by TOPREAL1:3; then k in dom(f|n) & k+1 in dom(f|n) & k+2 in dom(f|n) by A1,A2,GOBOARD2:4; then A4: (f|n)/.k = f/.k & (f|n)/.(k+1) = f/.(k+1) & (f|n)/.(k+2) = f/.(k+2) by TOPREAL1:1; let i1',j1',i2',j2' be Nat; thus thesis by A3,A4,Def7; end; theorem 1 <= k & k+2 <= len f & k+2 <= n & f|n goes_straight k,G implies f goes_straight k,G proof assume that A1: 1 <= k & k+2 <= len f and A2: k+2 <= n and A3: f|n goes_straight k,G; per cases; suppose len f <= n; hence thesis by A3,TOPREAL1:2; suppose n < len f; then len(f|n) = n by TOPREAL1:3; then k in dom(f|n) & k+1 in dom(f|n) & k+2 in dom(f|n) by A1,A2,GOBOARD2:4; then A4: (f|n)/.k = f/.k & (f|n)/.(k+1) = f/.(k+1) & (f|n)/.(k+2) = f/.(k+2) by TOPREAL1:1; let i1',j1',i2',j2' be Nat; thus thesis by A3,A4,Def8; end; theorem 1 < k & k+1 <= len f1 & k+1 <= len f2 & f1 is_sequence_on G & f1|k = f2|k & f1 turns_right k-'1,G & f2 turns_right k-'1,G implies f1|(k+1) = f2|(k+1) proof assume that A1: 1 < k & k+1 <= len f1 and A2: k+1 <= len f2 and A3: f1 is_sequence_on G and A4: f1|k = f2|k and A5: f1 turns_right k-'1,G and A6: f2 turns_right k-'1,G; A7: 1 <= k-'1 by A1,JORDAN3:12; A8: k = k-'1+1 by A1,AMI_5:4; k <= k+1 by NAT_1:37; then A9: k <= len f1 & k <= len f2 by A1,A2,AXIOMS:22; then A10: k <= len(f1|k) by TOPREAL1:3; k-'1 <= k by GOBOARD9:2; then k-'1 <= len(f1|k) by A9,TOPREAL1:3; then A11: k-'1 in dom(f1|k) & k in dom(f1|k) by A1,A7,A10,FINSEQ_3:27; then A12: f1/.(k-'1) = (f1|k)/.(k-'1) & f1/.k = (f1|k)/.k by TOPREAL1:1; A13: f2/.(k-'1) = (f2|k)/.(k-'1) & f2/.k = (f2|k)/.k by A4,A11,TOPREAL1:1; A14: k+1 = k-'1+(1+1) by A8,XCMPLX_1:1; consider i1,j1,i2,j2 being Nat such that A15: [i1,j1] in Indices G & f1/.(k-'1) = G*(i1,j1) and A16: [i2,j2] in Indices G & f1/.k = G*(i2,j2) and A17: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A3,A7,A8,A9,JORDAN8:6; A18: i1+1 > i1 & i2+1 > i2 & j1+1 > j1 & j2+1 > j2 by NAT_1:38; now per cases by A17; suppose A19: i1 = i2 & j1+1 = j2; hence f1/.(k+1) = G*(i2+1,j2) by A5,A8,A14,A15,A16,A18,Def6 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A19,Def6; suppose A20: i1+1 = i2 & j1 = j2; hence f1/.(k+1) = G*(i2,j2-'1) by A5,A8,A14,A15,A16,A18,Def6 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A20,Def6; suppose A21: i1 = i2+1 & j1 = j2; hence f1/.(k+1) = G*(i2,j2+1) by A5,A8,A14,A15,A16,A18,Def6 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A21,Def6; suppose A22: i1 = i2 & j1 = j2+1; hence f1/.(k+1) = G*(i2-'1,j2) by A5,A8,A14,A15,A16,A18,Def6 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A22,Def6; end; hence f1|(k+1) = (f2|k)^<*f2/.(k+1)*> by A1,A4,JORDAN8:2 .= f2|(k+1) by A2,JORDAN8:2; end; theorem 1 < k & k+1 <= len f1 & k+1 <= len f2 & f1 is_sequence_on G & f1|k = f2|k & f1 turns_left k-'1,G & f2 turns_left k-'1,G implies f1|(k+1) = f2|(k+1) proof assume that A1: 1 < k & k+1 <= len f1 and A2: k+1 <= len f2 and A3: f1 is_sequence_on G and A4: f1|k = f2|k and A5: f1 turns_left k-'1,G and A6: f2 turns_left k-'1,G; A7: 1 <= k-'1 by A1,JORDAN3:12; A8: k = k-'1+1 by A1,AMI_5:4; k <= k+1 by NAT_1:37; then A9: k <= len f1 & k <= len f2 by A1,A2,AXIOMS:22; then A10: k <= len(f1|k) by TOPREAL1:3; k-'1 <= k by GOBOARD9:2; then k-'1 <= len(f1|k) by A9,TOPREAL1:3; then A11: k-'1 in dom(f1|k) & k in dom(f1|k) by A1,A7,A10,FINSEQ_3:27; then A12: f1/.(k-'1) = (f1|k)/.(k-'1) & f1/.k = (f1|k)/.k by TOPREAL1:1; A13: f2/.(k-'1) = (f2|k)/.(k-'1) & f2/.k = (f2|k)/.k by A4,A11,TOPREAL1:1; A14: k+1 = k-'1+(1+1) by A8,XCMPLX_1:1; consider i1,j1,i2,j2 being Nat such that A15: [i1,j1] in Indices G & f1/.(k-'1) = G*(i1,j1) and A16: [i2,j2] in Indices G & f1/.k = G*(i2,j2) and A17: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A3,A7,A8,A9,JORDAN8:6; A18: i1+1 > i1 & i2+1 > i2 & j1+1 > j1 & j2+1 > j2 by NAT_1:38; now per cases by A17; suppose A19: i1 = i2 & j1+1 = j2; hence f1/.(k+1) = G*(i2-'1,j2) by A5,A8,A14,A15,A16,A18,Def7 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A19,Def7; suppose A20: i1+1 = i2 & j1 = j2; hence f1/.(k+1) = G*(i2,j2+1) by A5,A8,A14,A15,A16,A18,Def7 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A20,Def7; suppose A21: i1 = i2+1 & j1 = j2; hence f1/.(k+1) = G*(i2,j2-'1) by A5,A8,A14,A15,A16,A18,Def7 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A21,Def7; suppose A22: i1 = i2 & j1 = j2+1; hence f1/.(k+1) = G*(i2+1,j2) by A5,A8,A14,A15,A16,A18,Def7 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A22,Def7; end; hence f1|(k+1) = (f2|k)^<*f2/.(k+1)*> by A1,A4,JORDAN8:2 .= f2|(k+1) by A2,JORDAN8:2; end; theorem 1 < k & k+1 <= len f1 & k+1 <= len f2 & f1 is_sequence_on G & f1|k = f2|k & f1 goes_straight k-'1,G & f2 goes_straight k-'1,G implies f1|(k+1) = f2|(k+1) proof assume that A1: 1 < k & k+1 <= len f1 and A2: k+1 <= len f2 and A3: f1 is_sequence_on G and A4: f1|k = f2|k and A5: f1 goes_straight k-'1,G and A6: f2 goes_straight k-'1,G; A7: 1 <= k-'1 by A1,JORDAN3:12; A8: k = k-'1+1 by A1,AMI_5:4; k <= k+1 by NAT_1:37; then A9: k <= len f1 & k <= len f2 by A1,A2,AXIOMS:22; then A10: k <= len(f1|k) by TOPREAL1:3; k-'1 <= k by GOBOARD9:2; then k-'1 <= len(f1|k) by A9,TOPREAL1:3; then A11: k-'1 in dom(f1|k) & k in dom(f1|k) by A1,A7,A10,FINSEQ_3:27; then A12: f1/.(k-'1) = (f1|k)/.(k-'1) & f1/.k = (f1|k)/.k by TOPREAL1:1; A13: f2/.(k-'1) = (f2|k)/.(k-'1) & f2/.k = (f2|k)/.k by A4,A11,TOPREAL1:1; A14: k+1 = k-'1+(1+1) by A8,XCMPLX_1:1; consider i1,j1,i2,j2 being Nat such that A15: [i1,j1] in Indices G & f1/.(k-'1) = G*(i1,j1) and A16: [i2,j2] in Indices G & f1/.k = G*(i2,j2) and A17: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A3,A7,A8,A9,JORDAN8:6; A18: i1+1 > i1 & i2+1 > i2 & j1+1 > j1 & j2+1 > j2 by NAT_1:38; now per cases by A17; suppose A19: i1 = i2 & j1+1 = j2; hence f1/.(k+1) = G*(i2,j2+1) by A5,A8,A14,A15,A16,A18,Def8 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A19,Def8; suppose A20: i1+1 = i2 & j1 = j2; hence f1/.(k+1) = G*(i2+1,j2) by A5,A8,A14,A15,A16,A18,Def8 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A20,Def8; suppose A21: i1 = i2+1 & j1 = j2; hence f1/.(k+1) = G*(i2-'1,j2) by A5,A8,A14,A15,A16,A18,Def8 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A21,Def8; suppose A22: i1 = i2 & j1 = j2+1; hence f1/.(k+1) = G*(i2,j2-'1) by A5,A8,A14,A15,A16,A18,Def8 .= f2/.(k+1) by A4,A6,A8,A12,A13,A14,A15,A16,A18,A22,Def8; end; hence f1|(k+1) = (f2|k)^<*f2/.(k+1)*> by A1,A4,JORDAN8:2 .= f2|(k+1) by A2,JORDAN8:2; end; theorem for D being non empty set, M being Matrix of D st 1 <= i & i <= len M & 1 <= j & j <= width M holds M*(i,j) in Values M by Lm1;