Copyright (c) 2001 Association of Mizar Users
environ vocabulary FINSEQ_1, EUCLID, GOBOARD1, TOPREAL1, BOOLE, MATRIX_1, MCART_1, ORDINAL2, FUNCT_5, RELAT_1, REALSET1, SUBSET_1, PSCOMP_1, COMPTS_1, PRE_TOPC, TARSKI, FINSEQ_4, TREES_1, ARYTM_1, ABSVALUE, SPPOL_1, JORDAN1E, JORDAN9, FINSEQ_6, FINSEQ_5, JORDAN6, TOPREAL2, RELAT_2, JORDAN8, FUNCT_1, RFINSEQ, ARYTM_3, JORDAN1A; notation TARSKI, XBOOLE_0, XCMPLX_0, XREAL_0, NAT_1, ABSVALUE, RELAT_1, FUNCT_1, BINARITH, FUNCT_2, FINSEQ_1, FINSEQ_4, FINSEQ_5, FINSEQ_6, MATRIX_1, STRUCT_0, PRE_TOPC, COMPTS_1, CONNSP_1, RFINSEQ, EUCLID, TOPREAL1, TOPREAL2, GOBOARD1, SPPOL_1, PSCOMP_1, JORDAN6, JORDAN8, JORDAN9, JORDAN1A, JORDAN1E; constructors TOPREAL2, FINSEQ_4, REALSET1, GOBOARD9, GOBRD13, PSCOMP_1, CONNSP_1, GROUP_1, REAL_1, JORDAN6, JORDAN9, JORDAN5C, JORDAN1E, JORDAN1A, JORDAN8, CARD_4, BINARITH, RFINSEQ; clusters RELSET_1, SPRECT_1, SPRECT_3, TOPREAL6, XREAL_0, PSCOMP_1, REVROT_1, JORDAN1A, JORDAN1E, JORDAN8, NAT_1, MEMBERED; requirements NUMERALS, SUBSET, BOOLE, REAL, ARITHM; definitions TARSKI, XBOOLE_0; theorems AXIOMS, JORDAN8, REAL_1, NAT_1, GOBOARD7, GOBOARD5, SPRECT_3, ABSVALUE, GOBOARD1, JORDAN6, PSCOMP_1, TARSKI, TOPREAL3, SPRECT_2, FINSEQ_6, RELAT_1, FINSEQ_5, TOPREAL1, PRE_TOPC, JORDAN5B, FINSEQ_1, JORDAN1E, EXTENS_1, JORDAN1A, REVROT_1, JORDAN9, JORDAN1B, FINSEQ_3, UNIFORM1, FINSEQ_4, GROUP_5, JORDAN1D, SPRECT_5, RFINSEQ, BINARITH, XBOOLE_0, XBOOLE_1, SQUARE_1, XCMPLX_1; begin reserve i,j,k,m,n,l for Nat, f for FinSequence of the carrier of TOP-REAL 2, G for Go-board; theorem Th1: f is_sequence_on G & LSeg(G*(i,j),G*(i,k)) meets L~f & [i,j] in Indices G & [i,k] in Indices G & j <= k implies ex n st j <= n & n <= k & G*(i,n)`2 = inf(proj2.:(LSeg(G*(i,j),G*(i,k)) /\ L~f)) proof set X = LSeg(G*(i,j),G*(i,k)) /\ L~f; assume that A1: f is_sequence_on G and A2: LSeg(G*(i,j),G*(i,k)) meets L~f and A3: [i,j] in Indices G & [i,k] in Indices G and A4: j <= k; proj2.:X = (proj2|X).:X by EXTENS_1:1 .= (proj2||X).:X by PSCOMP_1:def 26; then A5: inf(proj2.:X) = inf((proj2||X).: [#]((TOP-REAL 2)|X)) by PRE_TOPC:def 10 .= inf((proj2||X).: the carrier of ((TOP-REAL 2)|X)) by PRE_TOPC:12 .= inf(proj2||X) by PSCOMP_1:def 20 .= S-bound X by PSCOMP_1:def 33; ex x being set st x in LSeg(G*(i,j),G*(i,k)) & x in L~f by A2,XBOOLE_0:3; then reconsider X1=X as non empty compact Subset of TOP-REAL 2 by PSCOMP_1: 64,XBOOLE_0:def 3; consider p being set such that A6: p in S-most X1 by XBOOLE_0:def 1; reconsider p as Point of TOP-REAL 2 by A6; A7: p`2 = (S-min X)`2 by A6,PSCOMP_1:118 .= inf(proj2.:X) by A5,PSCOMP_1:114; p in LSeg(SW-corner X, SE-corner X)/\X by A6,PSCOMP_1:def 41; then A8: p in X by XBOOLE_0:def 3; then p in L~f by XBOOLE_0:def 3; then p in union { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TOPREAL1:def 6; then consider Y being set such that A9: p in Y and A10: Y in { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TARSKI:def 4; consider i1 being Nat such that A11: Y = LSeg(f,i1) and A12: 1 <= i1 and A13: i1+1 <= len f by A10; A14: p in LSeg(f/.i1,f/.(i1+1)) by A9,A11,A12,A13,TOPREAL1:def 5; i1 <= len f by A13,NAT_1:38; then i1 in Seg len f by A12,FINSEQ_1:3; then A15: i1 in dom f by FINSEQ_1:def 3; then A16: f is special by A1,JORDAN8:7,RELAT_1:60; 1 < i1+1 by A12,NAT_1:38; then i1+1 in Seg len f by A13,FINSEQ_1:3; then A17: i1+1 in dom f by FINSEQ_1:def 3; consider i0,j0 being Nat such that A18: [i0,j0] in Indices G & f/.i1 = G*(i0,j0) by A1,A15,GOBOARD1:def 11; consider io,jo being Nat such that A19: [io,jo] in Indices G & f/.(i1+1) = G*(io,jo) by A1,A17,GOBOARD1:def 11; A20: 1 <= i & i <= len G & 1 <= j & j <= width G by A3,GOBOARD5:1; A21: 1 <= i & i <= len G & 1 <= k & k <= width G by A3,GOBOARD5:1; A22: 1 <= i0 & i0 <= len G & 1 <= j0 & j0 <= width G by A18,GOBOARD5:1; A23: 1 <= io & io <= len G & 1 <= jo & jo <= width G by A19,GOBOARD5:1; A24: G*(i,j)`1 = G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,k)`1 by A21,GOBOARD5:3; A25: p in LSeg(G*(i,j),G*(i,k)) by A8,XBOOLE_0:def 3; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A26: G*(i,j)`2 <= p`2 & p`2 <= G*(i,k)`2 by A25,TOPREAL1:10; ex n st j <= n & n <= k & G*(i,n) = p proof per cases by A12,A13,A16,TOPREAL1:def 7; suppose A27: (f/.i1)`1 = (f/.(i1+1))`1; G*(i0,j)`1 = G*(i0,1)`1 by A20,A22,GOBOARD5:3 .= G*(i0,j0)`1 by A22,GOBOARD5:3 .= p`1 by A14,A18,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; then A28: i0<=i & i0>=i by A20,A22,GOBOARD5:4; then A29: i=i0 by AXIOMS:21; G*(io,j)`1 = G*(io,1)`1 by A20,A23,GOBOARD5:3 .= G*(io,jo)`1 by A23,GOBOARD5:3 .= p`1 by A14,A19,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; then A30: io<=i & io>=i by A20,A23,GOBOARD5:4; then A31: i=io by AXIOMS:21; thus thesis proof per cases; suppose A32: (f/.i1)`2 <= (f/.(i1+1))`2; thus thesis proof per cases; suppose A33: (f/.i1) in LSeg(G*(i,j),G*(i,k)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.i1 in L~f by A15,GOBOARD1:16; then f/.i1 in X1 by A33,XBOOLE_0:def 3; then A34: p`2 <= (f/.i1)`2 by A5,A7,PSCOMP_1:71; p`2 >= (f/.i1)`2 by A14,A32,TOPREAL1:10; then A35: p`2 = (f/.i1)`2 by A34,AXIOMS:21; take n=j0; A36: p in LSeg(G*(i,j),G*(i,k)) by A8,XBOOLE_0:def 3; then A37: p`1 = G*(i,j)`1 by A24,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A22,GOBOARD5:3; A38: p`2 = G*(1,j0)`2 by A18,A22,A35,GOBOARD5:2 .= G*(i,n)`2 by A20,A22,GOBOARD5:2; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A39: G*(i,j)`2 <= G*(i,n)`2 & G*(i,n)`2 <= G*(i,k)`2 by A36,A38, TOPREAL1:10; hence j <= n by A20,A22,GOBOARD5:5; thus n <= k by A21,A22,A39,GOBOARD5:5; thus thesis by A37,A38,TOPREAL3:11; suppose A40: not f/.i1 in LSeg(G*(i,j),G*(i,k)); A41: (f/.i1)`1 = p`1 by A14,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; thus thesis proof per cases by A24,A40,A41,GOBOARD7:8; suppose A42: (f/.i1)`2 < G*(i,j)`2; then A43: G*(i,j0)`2 < G*(i,j)`2 by A18,A28,AXIOMS:21; j0<=j by A18,A20,A22,A29,A42,GOBOARD5:5; then A44: j0<j by A43,AXIOMS:21; j0<=jo+0 by A18,A19,A22,A23,A29,A31,A32,GOBOARD5:5; then j0-jo <= 0 by REAL_1:86; then -(j0-jo) >= -0 by REAL_1:50; then A45: jo-j0 >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0) + abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then abs(-(j0-jo)) = 1 by ABSVALUE:17; then abs(jo-j0) = 1 by XCMPLX_1:143; then jo-j0 = 1 by A45,ABSVALUE:def 1; then j0+jo-j0 = j0+1 by XCMPLX_1:29; then jo+(j0-j0) = j0+1 by XCMPLX_1:29; then j0+1=jo+0 by XCMPLX_1:14; then A46: jo<=j by A44,NAT_1:38; p`2 <= G*(io,jo)`2 by A14,A19,A32,TOPREAL1:10; then p`2 <= G*(1,jo)`2 by A23,GOBOARD5:2; then p`2 <= G*(i,jo)`2 by A20,A23,GOBOARD5:2; then G*(i,j)`2 <= G*(i,jo)`2 by A26,AXIOMS:22; then j<=jo by A20,A23,GOBOARD5:5; then A47: j=jo by A46,AXIOMS:21; take n=jo; A48: p`1 = G*(i,j)`1 by A24,A25,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A23,GOBOARD5:3; p`2 <= G*(io,jo)`2 by A14,A19,A32,TOPREAL1:10; then p`2 <= G*(1,jo)`2 by A23,GOBOARD5:2; then p`2 <= G*(i,jo)`2 by A20,A23,GOBOARD5:2; then p`2 = G*(i,j)`2 by A26,A47,AXIOMS:21; hence thesis by A4,A47,A48,TOPREAL3:11; suppose A49: (f/.i1)`2 > G*(i,k)`2; p`2 >= (f/.i1)`2 by A14,A32,TOPREAL1:10; hence thesis by A26,A49,AXIOMS:22; end; end; suppose A50: (f/.i1)`2 > (f/.(i1+1))`2; thus thesis proof per cases; suppose A51: (f/.(i1+1)) in LSeg(G*(i,j),G*(i,k)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.(i1+1) in L~f by A17,GOBOARD1:16; then f/.(i1+1) in X1 by A51,XBOOLE_0:def 3; then A52: p`2 <= (f/.(i1+1))`2 by A5,A7,PSCOMP_1:71; p`2 >= (f/.(i1+1))`2 by A14,A50,TOPREAL1:10; then A53: p`2 = (f/.(i1+1))`2 by A52,AXIOMS:21; take n=jo; A54: p in LSeg(G*(i,j),G*(i,k)) by A8,XBOOLE_0:def 3; then A55: p`1 = G*(i,j)`1 by A24,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A23,GOBOARD5:3; A56: p`2 = G*(1,jo)`2 by A19,A23,A53,GOBOARD5:2 .= G*(i,n)`2 by A20,A23,GOBOARD5:2; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A57: G*(i,j)`2 <= G*(i,n)`2 & G*(i,n)`2 <= G*(i,k)`2 by A54,A56, TOPREAL1:10; hence j <= n by A20,A23,GOBOARD5:5; thus n <= k by A21,A23,A57,GOBOARD5:5; thus thesis by A55,A56,TOPREAL3:11; suppose A58: not f/.(i1+1) in LSeg(G*(i,j),G*(i,k)); A59: (f/.(i1+1))`1 = p`1 by A14,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; thus thesis proof per cases by A24,A58,A59,GOBOARD7:8; suppose A60: (f/.(i1+1))`2 < G*(i,j)`2; then A61: G*(i,jo)`2 < G*(i,j)`2 by A19,A30,AXIOMS:21; jo<=j by A19,A20,A23,A31,A60,GOBOARD5:5; then A62: jo<j by A61,AXIOMS:21; jo<=j0+0 by A18,A19,A22,A23,A29,A31,A50,GOBOARD5:5; then jo-j0 <= 0 by REAL_1:86; then -(jo-j0) >= -0 by REAL_1:50; then A63: j0-jo >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then j0-jo = 1 by A63,ABSVALUE:def 1; then j0-(jo-jo) = jo+1 by XCMPLX_1:37; then jo+1=j0-0 by XCMPLX_1:14; then A64: j0<=j by A62,NAT_1:38; p`2 <= G*(i0,j0)`2 by A14,A18,A50,TOPREAL1:10; then p`2 <= G*(1,j0)`2 by A22,GOBOARD5:2; then p`2 <= G*(i,j0)`2 by A20,A22,GOBOARD5:2; then G*(i,j)`2 <= G*(i,j0)`2 by A26,AXIOMS:22; then j<=j0 by A20,A22,GOBOARD5:5; then A65: j=j0 by A64,AXIOMS:21; take n=j0; A66: p`1 = G*(i,j)`1 by A24,A25,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A22,GOBOARD5:3; p`2 <= G*(i0,j0)`2 by A14,A18,A50,TOPREAL1:10; then p`2 <= G*(1,j0)`2 by A22,GOBOARD5:2; then p`2 <= G*(i,j0)`2 by A20,A22,GOBOARD5:2; then p`2 = G*(i,j)`2 by A26,A65,AXIOMS:21; hence thesis by A4,A65,A66,TOPREAL3:11; suppose A67: (f/.(i1+1))`2 > G*(i,k)`2; p`2 >= (f/.(i1+1))`2 by A14,A50,TOPREAL1:10; hence thesis by A26,A67,AXIOMS:22; end; end; end; suppose (f/.i1)`2 = (f/.(i1+1))`2; then A68: p`2 = (f/.i1)`2 by A14,GOBOARD7:6; take n=j0; A69: p`1 = G*(i,j)`1 by A24,A25,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A22,GOBOARD5:3; A70: p`2 = G*(1,j0)`2 by A18,A22,A68,GOBOARD5:2 .= G*(i,n)`2 by A20,A22,GOBOARD5:2; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A71: G*(i,j)`2 <= G*(i,n)`2 & G*(i,n)`2 <= G*(i,k)`2 by A25,A70,TOPREAL1: 10; hence j <= n by A20,A22,GOBOARD5:5; thus n <= k by A21,A22,A71,GOBOARD5:5; thus thesis by A69,A70,TOPREAL3:11; end; hence ex n st j <= n & n <= k & G*(i,n)`2 = inf(proj2.:X) by A7; end; theorem f is_sequence_on G & LSeg(G*(i,j),G*(i,k)) meets L~f & [i,j] in Indices G & [i,k] in Indices G & j <= k implies ex n st j <= n & n <= k & G*(i,n)`2 = sup(proj2.:(LSeg(G*(i,j),G*(i,k)) /\ L~f)) proof set X = LSeg(G*(i,j),G*(i,k)) /\ L~f; assume that A1: f is_sequence_on G and A2: LSeg(G*(i,j),G*(i,k)) meets L~f and A3: [i,j] in Indices G & [i,k] in Indices G and A4: j <= k; proj2.:X = (proj2|X).:X by EXTENS_1:1 .= (proj2||X).:X by PSCOMP_1:def 26; then A5: sup(proj2.:X) = sup((proj2||X).: [#]((TOP-REAL 2)|X)) by PRE_TOPC:def 10 .= sup((proj2||X).: the carrier of ((TOP-REAL 2)|X)) by PRE_TOPC:12 .= sup(proj2||X) by PSCOMP_1:def 21 .= N-bound X by PSCOMP_1:def 31; ex x being set st x in LSeg(G*(i,j),G*(i,k)) & x in L~f by A2,XBOOLE_0:3; then reconsider X1=X as non empty compact Subset of TOP-REAL 2 by PSCOMP_1: 64,XBOOLE_0:def 3; consider p being set such that A6: p in N-most X1 by XBOOLE_0:def 1; reconsider p as Point of TOP-REAL 2 by A6; A7: p`2 = (N-min X)`2 by A6,PSCOMP_1:98 .= sup(proj2.:X) by A5,PSCOMP_1:94; p in LSeg(NW-corner X, NE-corner X)/\X by A6,PSCOMP_1:def 39; then A8: p in X by XBOOLE_0:def 3; then p in L~f by XBOOLE_0:def 3; then p in union { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TOPREAL1:def 6; then consider Y being set such that A9: p in Y and A10: Y in { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TARSKI:def 4; consider i1 being Nat such that A11: Y = LSeg(f,i1) and A12: 1 <= i1 and A13: i1+1 <= len f by A10; A14: p in LSeg(f/.i1,f/.(i1+1)) by A9,A11,A12,A13,TOPREAL1:def 5; i1 <= len f by A13,NAT_1:38; then i1 in Seg len f by A12,FINSEQ_1:3; then A15: i1 in dom f by FINSEQ_1:def 3; then A16: f is special by A1,JORDAN8:7,RELAT_1:60; 1 < i1+1 by A12,NAT_1:38; then i1+1 in Seg len f by A13,FINSEQ_1:3; then A17: i1+1 in dom f by FINSEQ_1:def 3; consider i0,j0 being Nat such that A18: [i0,j0] in Indices G & f/.i1 = G*(i0,j0) by A1,A15,GOBOARD1:def 11; consider io,jo being Nat such that A19: [io,jo] in Indices G & f/.(i1+1) = G*(io,jo) by A1,A17,GOBOARD1:def 11; A20: 1 <= i & i <= len G & 1 <= j & j <= width G by A3,GOBOARD5:1; A21: 1 <= i & i <= len G & 1 <= k & k <= width G by A3,GOBOARD5:1; A22: 1 <= i0 & i0 <= len G & 1 <= j0 & j0 <= width G by A18,GOBOARD5:1; A23: 1 <= io & io <= len G & 1 <= jo & jo <= width G by A19,GOBOARD5:1; A24: G*(i,j)`1 = G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,k)`1 by A21,GOBOARD5:3; A25: p in LSeg(G*(i,j),G*(i,k)) by A8,XBOOLE_0:def 3; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A26: G*(i,j)`2 <= p`2 & p`2 <= G*(i,k)`2 by A25,TOPREAL1:10; ex n st j <= n & n <= k & G*(i,n) = p proof per cases by A12,A13,A16,TOPREAL1:def 7; suppose A27: (f/.i1)`1 = (f/.(i1+1))`1; G*(i0,j)`1 = G*(i0,1)`1 by A20,A22,GOBOARD5:3 .= G*(i0,j0)`1 by A22,GOBOARD5:3 .= p`1 by A14,A18,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; then A28: i0<=i & i0>=i by A20,A22,GOBOARD5:4; then A29: i=i0 by AXIOMS:21; G*(io,j)`1 = G*(io,1)`1 by A20,A23,GOBOARD5:3 .= G*(io,jo)`1 by A23,GOBOARD5:3 .= p`1 by A14,A19,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; then A30: io<=i & io>=i by A20,A23,GOBOARD5:4; then A31: i=io by AXIOMS:21; thus thesis proof per cases; suppose A32: (f/.i1)`2 <= (f/.(i1+1))`2; thus thesis proof per cases; suppose A33: (f/.(i1+1)) in LSeg(G*(i,j),G*(i,k)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.(i1+1) in L~f by A17,GOBOARD1:16; then f/.(i1+1) in X1 by A33,XBOOLE_0:def 3; then A34: p`2 >= (f/.(i1+1))`2 by A5,A7,PSCOMP_1:71; p`2 <= (f/.(i1+1))`2 by A14,A32,TOPREAL1:10; then A35: p`2 = (f/.(i1+1))`2 by A34,AXIOMS:21; take n=jo; A36: p in LSeg(G*(i,j),G*(i,k)) by A8,XBOOLE_0:def 3; then A37: p`1 = G*(i,j)`1 by A24,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A23,GOBOARD5:3; A38: p`2 = G*(1,jo)`2 by A19,A23,A35,GOBOARD5:2 .= G*(i,n)`2 by A20,A23,GOBOARD5:2; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A39: G*(i,j)`2 <= G*(i,n)`2 & G*(i,n)`2 <= G*(i,k)`2 by A36,A38, TOPREAL1:10; hence j <= n by A20,A23,GOBOARD5:5; thus n <= k by A21,A23,A39,GOBOARD5:5; thus thesis by A37,A38,TOPREAL3:11; suppose A40: not f/.(i1+1) in LSeg(G*(i,j),G*(i,k)); A41: (f/.(i1+1))`1 = p`1 by A14,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; thus thesis proof per cases by A24,A40,A41,GOBOARD7:8; suppose A42: (f/.(i1+1))`2 > G*(i,k)`2; then A43: G*(i,jo)`2 > G*(i,k)`2 by A19,A30,AXIOMS:21; jo>=k by A19,A21,A23,A31,A42,GOBOARD5:5; then A44: jo>k by A43,AXIOMS:21; j0<=jo+0 by A18,A19,A22,A23,A29,A31,A32,GOBOARD5:5; then j0-jo <= 0 by REAL_1:86; then -(j0-jo) >= -0 by REAL_1:50; then A45: jo-j0 >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then abs(-(j0-jo)) = 1 by ABSVALUE:17; then abs(jo-j0) = 1 by XCMPLX_1:143; then jo-j0 = 1 by A45,ABSVALUE:def 1; then j0+jo-j0 = j0+1 by XCMPLX_1:29; then jo+(j0-j0) = j0+1 by XCMPLX_1:29; then j0+1=jo+0 by XCMPLX_1:14; then A46: j0>=k by A44,NAT_1:38; p`2 >= G*(i0,j0)`2 by A14,A18,A32,TOPREAL1:10; then p`2 >= G*(1,j0)`2 by A22,GOBOARD5:2; then p`2 >= G*(i,j0)`2 by A20,A22,GOBOARD5:2; then G*(i,k)`2 >= G*(i,j0)`2 by A26,AXIOMS:22; then k>=j0 by A21,A22,GOBOARD5:5; then A47: k=j0 by A46,AXIOMS:21; take n=j0; A48: p`1 = G*(i,j)`1 by A24,A25,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A22,GOBOARD5:3; p`2 >= G*(i0,j0)`2 by A14,A18,A32,TOPREAL1:10; then p`2 >= G*(1,j0)`2 by A22,GOBOARD5:2; then p`2 >= G*(i,j0)`2 by A20,A22,GOBOARD5:2; then p`2 = G*(i,k)`2 by A26,A47,AXIOMS:21; hence thesis by A4,A47,A48,TOPREAL3:11; suppose A49: (f/.(i1+1))`2 < G*(i,j)`2; p`2 <= (f/.(i1+1))`2 by A14,A32,TOPREAL1:10; hence thesis by A26,A49,AXIOMS:22; end; end; suppose A50: (f/.i1)`2 > (f/.(i1+1))`2; thus thesis proof per cases; suppose A51: f/.i1 in LSeg(G*(i,j),G*(i,k)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.i1 in L~f by A15,GOBOARD1:16; then f/.i1 in X1 by A51,XBOOLE_0:def 3; then A52: p`2 >= (f/.i1)`2 by A5,A7,PSCOMP_1:71; p`2 <= (f/.i1)`2 by A14,A50,TOPREAL1:10; then A53: p`2 = (f/.i1)`2 by A52,AXIOMS:21; take n=j0; A54: p in LSeg(G*(i,j),G*(i,k)) by A8,XBOOLE_0:def 3; then A55: p`1 = G*(i,j)`1 by A24,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A22,GOBOARD5:3; A56: p`2 = G*(1,j0)`2 by A18,A22,A53,GOBOARD5:2 .= G*(i,n)`2 by A20,A22,GOBOARD5:2; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A57: G*(i,j)`2 <= G*(i,n)`2 & G*(i,n)`2 <= G*(i,k)`2 by A54,A56, TOPREAL1:10; hence j <= n by A20,A22,GOBOARD5:5; thus n <= k by A21,A22,A57,GOBOARD5:5; thus thesis by A55,A56,TOPREAL3:11; suppose A58: not f/.i1 in LSeg(G*(i,j),G*(i,k)); A59: (f/.i1)`1 = p`1 by A14,A27,GOBOARD7:5 .= G*(i,j)`1 by A24,A25,GOBOARD7:5; thus thesis proof per cases by A24,A58,A59,GOBOARD7:8; suppose A60: (f/.i1)`2 > G*(i,k)`2; then A61: G*(i,j0)`2 > G*(i,k)`2 by A18,A28,AXIOMS:21; j0>=k by A18,A21,A22,A29,A60,GOBOARD5:5; then A62: j0>k by A61,AXIOMS:21; jo<=j0+0 by A18,A19,A22,A23,A29,A31,A50,GOBOARD5:5; then jo-j0 <= 0 by REAL_1:86; then -(jo-j0) >= -0 by REAL_1:50; then A63: j0-jo >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then j0-jo = 1 by A63,ABSVALUE:def 1; then j0-(jo-jo) = jo+1 by XCMPLX_1:37; then jo+1=j0-0 by XCMPLX_1:14; then A64: jo>=k by A62,NAT_1:38; p`2 >= G*(io,jo)`2 by A14,A19,A50,TOPREAL1:10; then p`2 >= G*(1,jo)`2 by A23,GOBOARD5:2; then p`2 >= G*(i,jo)`2 by A20,A23,GOBOARD5:2; then G*(i,k)`2 >= G*(i,jo)`2 by A26,AXIOMS:22; then k>=jo by A21,A23,GOBOARD5:5; then A65: k=jo by A64,AXIOMS:21; take n=jo; A66: p`1 = G*(i,j)`1 by A24,A25,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A23,GOBOARD5:3; p`2 >= G*(io,jo)`2 by A14,A19,A50,TOPREAL1:10; then p`2 >= G*(1,jo)`2 by A23,GOBOARD5:2; then p`2 >= G*(i,jo)`2 by A20,A23,GOBOARD5:2; then p`2 = G*(i,k)`2 by A26,A65,AXIOMS:21; hence thesis by A4,A65,A66,TOPREAL3:11; suppose A67: (f/.i1)`2 < G*(i,j)`2; p`2 <= (f/.i1)`2 by A14,A50,TOPREAL1:10; hence thesis by A26,A67,AXIOMS:22; end; end; end; suppose (f/.i1)`2 = (f/.(i1+1))`2; then A68: p`2 = (f/.i1)`2 by A14,GOBOARD7:6; take n=j0; A69: p`1 = G*(i,j)`1 by A24,A25,GOBOARD7:5 .= G*(i,1)`1 by A20,GOBOARD5:3 .= G*(i,n)`1 by A20,A22,GOBOARD5:3; A70: p`2 = G*(1,j0)`2 by A18,A22,A68,GOBOARD5:2 .= G*(i,n)`2 by A20,A22,GOBOARD5:2; G*(i,j)`2 <= G*(i,k)`2 by A4,A20,A21,SPRECT_3:24; then A71: G*(i,j)`2 <= G*(i,n)`2 & G*(i,n)`2 <= G*(i,k)`2 by A25,A70,TOPREAL1: 10; hence j <= n by A20,A22,GOBOARD5:5; thus n <= k by A21,A22,A71,GOBOARD5:5; thus thesis by A69,A70,TOPREAL3:11; end; hence ex n st j <= n & n <= k & G*(i,n)`2 = sup(proj2.:X) by A7; end; theorem f is_sequence_on G & LSeg(G*(j,i),G*(k,i)) meets L~f & [j,i] in Indices G & [k,i] in Indices G & j <= k implies ex n st j <= n & n <= k & G*(n,i)`1 = inf(proj1.:(LSeg(G*(j,i),G*(k,i)) /\ L~f)) proof set X = LSeg(G*(j,i),G*(k,i)) /\ L~f; assume that A1: f is_sequence_on G and A2: LSeg(G*(j,i),G*(k,i)) meets L~f and A3: [j,i] in Indices G & [k,i] in Indices G and A4: j <= k; proj1.:X = (proj1|X).:X by EXTENS_1:1 .= (proj1||X).:X by PSCOMP_1:def 26; then A5: inf(proj1.:X) = inf((proj1||X).: [#]((TOP-REAL 2)|X)) by PRE_TOPC:def 10 .= inf((proj1||X).: the carrier of ((TOP-REAL 2)|X)) by PRE_TOPC:12 .= inf(proj1||X) by PSCOMP_1:def 20 .= W-bound X by PSCOMP_1:def 30; ex x being set st x in LSeg(G*(j,i),G*(k,i)) & x in L~f by A2,XBOOLE_0:3; then reconsider X1=X as non empty compact Subset of TOP-REAL 2 by PSCOMP_1: 64,XBOOLE_0:def 3; consider p being set such that A6: p in W-most X1 by XBOOLE_0:def 1; reconsider p as Point of TOP-REAL 2 by A6; A7: p`1 = (W-min X)`1 by A6,PSCOMP_1:88 .= inf(proj1.:X) by A5,PSCOMP_1:84; p in LSeg(SW-corner X, NW-corner X)/\X by A6,PSCOMP_1:def 38; then A8: p in X by XBOOLE_0:def 3; then p in L~f by XBOOLE_0:def 3; then p in union { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TOPREAL1:def 6; then consider Y being set such that A9: p in Y and A10: Y in { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TARSKI:def 4; consider i1 being Nat such that A11: Y = LSeg(f,i1) and A12: 1 <= i1 and A13: i1+1 <= len f by A10; A14: p in LSeg(f/.i1,f/.(i1+1)) by A9,A11,A12,A13,TOPREAL1:def 5; i1 <= len f by A13,NAT_1:38; then i1 in Seg len f by A12,FINSEQ_1:3; then A15: i1 in dom f by FINSEQ_1:def 3; then A16: f is special by A1,JORDAN8:7,RELAT_1:60; 1 < i1+1 by A12,NAT_1:38; then i1+1 in Seg len f by A13,FINSEQ_1:3; then A17: i1+1 in dom f by FINSEQ_1:def 3; consider j0,i0 being Nat such that A18: [j0,i0] in Indices G & f/.i1 = G*(j0,i0) by A1,A15,GOBOARD1:def 11; consider jo,io being Nat such that A19: [jo,io] in Indices G & f/.(i1+1) = G*(jo,io) by A1,A17,GOBOARD1:def 11; A20: 1 <= j & j <= len G & 1 <= i & i <= width G by A3,GOBOARD5:1; A21: 1 <= k & k <= len G & 1 <= i & i <= width G by A3,GOBOARD5:1; A22: 1 <= j0 & j0 <= len G & 1 <= i0 & i0 <= width G by A18,GOBOARD5:1; A23: 1 <= jo & jo <= len G & 1 <= io & io <= width G by A19,GOBOARD5:1; A24: G*(j,i)`2 = G*(1,i)`2 by A20,GOBOARD5:2 .= G*(k,i)`2 by A21,GOBOARD5:2; A25: p in LSeg(G*(j,i),G*(k,i)) by A8,XBOOLE_0:def 3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A26: G*(j,i)`1 <= p`1 & p`1 <= G*(k,i)`1 by A25,TOPREAL1:9; ex n st j <= n & n <= k & G*(n,i) = p proof per cases by A12,A13,A16,TOPREAL1:def 7; suppose A27: (f/.i1)`2 = (f/.(i1+1))`2; G*(j,i0)`2 = G*(1,i0)`2 by A20,A22,GOBOARD5:2 .= G*(j0,i0)`2 by A22,GOBOARD5:2 .= p`2 by A14,A18,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; then A28: i0<=i & i0>=i by A20,A22,GOBOARD5:5; then A29: i=i0 by AXIOMS:21; G*(j,io)`2 = G*(1,io)`2 by A20,A23,GOBOARD5:2 .= G*(jo,io)`2 by A23,GOBOARD5:2 .= p`2 by A14,A19,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; then A30: io<=i & io>=i by A20,A23,GOBOARD5:5; then A31: i=io by AXIOMS:21; thus thesis proof per cases; suppose A32: (f/.i1)`1 <= (f/.(i1+1))`1; thus thesis proof per cases; suppose A33: (f/.i1) in LSeg(G*(j,i),G*(k,i)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.i1 in L~f by A15,GOBOARD1:16; then f/.i1 in X1 by A33,XBOOLE_0:def 3; then A34: p`1 <= (f/.i1)`1 by A5,A7,PSCOMP_1:71; p`1 >= (f/.i1)`1 by A14,A32,TOPREAL1:9; then A35: p`1 = (f/.i1)`1 by A34,AXIOMS:21; take n=j0; A36: p in LSeg(G*(j,i),G*(k,i)) by A8,XBOOLE_0:def 3; then A37: p`2 = G*(j,i)`2 by A24,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A22,GOBOARD5:2; A38: p`1 = G*(j0,1)`1 by A18,A22,A35,GOBOARD5:3 .= G*(n,i)`1 by A20,A22,GOBOARD5:3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A39: G*(j,i)`1 <= G*(n,i)`1 & G*(n,i)`1 <= G*(k,i)`1 by A36,A38, TOPREAL1:9; hence j <= n by A20,A22,GOBOARD5:4; thus n <= k by A21,A22,A39,GOBOARD5:4; thus thesis by A37,A38,TOPREAL3:11; suppose A40: not f/.i1 in LSeg(G*(j,i),G*(k,i)); A41: (f/.i1)`2 = p`2 by A14,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; thus thesis proof per cases by A24,A40,A41,GOBOARD7:9; suppose A42: (f/.i1)`1 < G*(j,i)`1; then A43: G*(j0,i)`1 < G*(j,i)`1 by A18,A28,AXIOMS:21; j0<=j by A18,A20,A22,A29,A42,GOBOARD5:4; then A44: j0<j by A43,AXIOMS:21; j0<=jo+0 by A18,A19,A22,A23,A29,A31,A32,GOBOARD5:4; then j0-jo <= 0 by REAL_1:86; then -(j0-jo) >= -0 by REAL_1:50; then A45: jo-j0 >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then abs(-(j0-jo)) = 1 by ABSVALUE:17; then abs(jo-j0) = 1 by XCMPLX_1:143; then jo-j0 = 1 by A45,ABSVALUE:def 1; then j0+jo-j0 = j0+1 by XCMPLX_1:29; then jo+(j0-j0) = j0+1 by XCMPLX_1:29; then j0+1=jo+0 by XCMPLX_1:14; then A46: jo<=j by A44,NAT_1:38; p`1 <= G*(jo,io)`1 by A14,A19,A32,TOPREAL1:9; then p`1 <= G*(jo,1)`1 by A23,GOBOARD5:3; then p`1 <= G*(jo,i)`1 by A20,A23,GOBOARD5:3; then G*(j,i)`1 <= G*(jo,i)`1 by A26,AXIOMS:22; then j<=jo by A20,A23,GOBOARD5:4; then A47: j=jo by A46,AXIOMS:21; take n=jo; A48: p`2 = G*(j,i)`2 by A24,A25,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A23,GOBOARD5:2; p`1 <= G*(jo,io)`1 by A14,A19,A32,TOPREAL1:9; then p`1 <= G*(jo,1)`1 by A23,GOBOARD5:3; then p`1 <= G*(jo,i)`1 by A20,A23,GOBOARD5:3; then p`1 = G*(j,i)`1 by A26,A47,AXIOMS:21; hence thesis by A4,A47,A48,TOPREAL3:11; suppose A49: (f/.i1)`1 > G*(k,i)`1; p`1 >= (f/.i1)`1 by A14,A32,TOPREAL1:9; hence thesis by A26,A49,AXIOMS:22; end; end; suppose A50: (f/.i1)`1 > (f/.(i1+1))`1; thus thesis proof per cases; suppose A51: (f/.(i1+1)) in LSeg(G*(j,i),G*(k,i)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.(i1+1) in L~f by A17,GOBOARD1:16; then f/.(i1+1) in X1 by A51,XBOOLE_0:def 3; then A52: p`1 <= (f/.(i1+1))`1 by A5,A7,PSCOMP_1:71; p`1 >= (f/.(i1+1))`1 by A14,A50,TOPREAL1:9; then A53: p`1 = (f/.(i1+1))`1 by A52,AXIOMS:21; take n=jo; A54: p in LSeg(G*(j,i),G*(k,i)) by A8,XBOOLE_0:def 3; then A55: p`2 = G*(j,i)`2 by A24,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A23,GOBOARD5:2; A56: p`1 = G*(jo,1)`1 by A19,A23,A53,GOBOARD5:3 .= G*(n,i)`1 by A20,A23,GOBOARD5:3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A57: G*(j,i)`1 <= G*(n,i)`1 & G*(n,i)`1 <= G*(k,i)`1 by A54,A56, TOPREAL1:9; hence j <= n by A20,A23,GOBOARD5:4; thus n <= k by A21,A23,A57,GOBOARD5:4; thus thesis by A55,A56,TOPREAL3:11; suppose A58: not f/.(i1+1) in LSeg(G*(j,i),G*(k,i)); A59: (f/.(i1+1))`2 = p`2 by A14,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; thus thesis proof per cases by A24,A58,A59,GOBOARD7:9; suppose A60: (f/.(i1+1))`1 < G*(j,i)`1; then A61: G*(jo,i)`1 < G*(j,i)`1 by A19,A30,AXIOMS:21; jo<=j by A19,A20,A23,A31,A60,GOBOARD5:4; then A62: jo<j by A61,AXIOMS:21; jo<=j0+0 by A18,A19,A22,A23,A29,A31,A50,GOBOARD5:4; then jo-j0 <= 0 by REAL_1:86; then -(jo-j0) >= -0 by REAL_1:50; then A63: j0-jo >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then j0-jo = 1 by A63,ABSVALUE:def 1; then j0-(jo-jo) = jo+1 by XCMPLX_1:37; then jo+1=j0-0 by XCMPLX_1:14; then A64: j0<=j by A62,NAT_1:38; p`1 <= G*(j0,i0)`1 by A14,A18,A50,TOPREAL1:9; then p`1 <= G*(j0,1)`1 by A22,GOBOARD5:3; then p`1 <= G*(j0,i)`1 by A20,A22,GOBOARD5:3; then G*(j,i)`1 <= G*(j0,i)`1 by A26,AXIOMS:22; then j<=j0 by A20,A22,GOBOARD5:4; then A65: j=j0 by A64,AXIOMS:21; take n=j0; A66: p`2 = G*(j,i)`2 by A24,A25,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A22,GOBOARD5:2; p`1 <= G*(j0,i0)`1 by A14,A18,A50,TOPREAL1:9; then p`1 <= G*(j0,1)`1 by A22,GOBOARD5:3; then p`1 <= G*(j0,i)`1 by A20,A22,GOBOARD5:3; then p`1 = G*(j,i)`1 by A26,A65,AXIOMS:21; hence thesis by A4,A65,A66,TOPREAL3:11; suppose A67: (f/.(i1+1))`1 > G*(k,i)`1; p`1 >= (f/.(i1+1))`1 by A14,A50,TOPREAL1:9; hence thesis by A26,A67,AXIOMS:22; end; end; end; suppose (f/.i1)`1 = (f/.(i1+1))`1; then A68: p`1 = (f/.i1)`1 by A14,GOBOARD7:5; take n=j0; A69: p`2 = G*(j,i)`2 by A24,A25,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A22,GOBOARD5:2; A70: p`1 = G*(j0,1)`1 by A18,A22,A68,GOBOARD5:3 .= G*(n,i)`1 by A20,A22,GOBOARD5:3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A71: G*(j,i)`1 <= G*(n,i)`1 & G*(n,i)`1 <= G*(k,i)`1 by A25,A70,TOPREAL1: 9; hence j <= n by A20,A22,GOBOARD5:4; thus n <= k by A21,A22,A71,GOBOARD5:4; thus thesis by A69,A70,TOPREAL3:11; end; hence ex n st j <= n & n <= k & G*(n,i)`1 = inf(proj1.:X) by A7; end; theorem f is_sequence_on G & LSeg(G*(j,i),G*(k,i)) meets L~f & [j,i] in Indices G & [k,i] in Indices G & j <= k implies ex n st j <= n & n <= k & G*(n,i)`1 = sup(proj1.:(LSeg(G*(j,i),G*(k,i)) /\ L~f)) proof set X = LSeg(G*(j,i),G*(k,i)) /\ L~f; assume that A1: f is_sequence_on G and A2: LSeg(G*(j,i),G*(k,i)) meets L~f and A3: [j,i] in Indices G & [k,i] in Indices G and A4: j <= k; proj1.:X = (proj1|X).:X by EXTENS_1:1 .= (proj1||X).:X by PSCOMP_1:def 26; then A5: sup(proj1.:X) = sup((proj1||X).: [#]((TOP-REAL 2)|X)) by PRE_TOPC:def 10 .= sup((proj1||X).: the carrier of ((TOP-REAL 2)|X)) by PRE_TOPC:12 .= sup(proj1||X) by PSCOMP_1:def 21 .= E-bound X by PSCOMP_1:def 32; ex x being set st x in LSeg(G*(j,i),G*(k,i)) & x in L~f by A2,XBOOLE_0:3; then reconsider X1=X as non empty compact Subset of TOP-REAL 2 by PSCOMP_1: 64,XBOOLE_0:def 3; consider p being set such that A6: p in E-most X1 by XBOOLE_0:def 1; reconsider p as Point of TOP-REAL 2 by A6; A7: p`1 = (E-min X)`1 by A6,PSCOMP_1:108 .= sup(proj1.:X) by A5,PSCOMP_1:104; p in LSeg(SE-corner X, NE-corner X)/\X by A6,PSCOMP_1:def 40; then A8: p in X by XBOOLE_0:def 3; then p in L~f by XBOOLE_0:def 3; then p in union { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TOPREAL1:def 6; then consider Y being set such that A9: p in Y and A10: Y in { LSeg(f,k1) where k1 is Nat : 1 <= k1 & k1+1 <= len f} by TARSKI:def 4; consider i1 being Nat such that A11: Y = LSeg(f,i1) and A12: 1 <= i1 and A13: i1+1 <= len f by A10; A14: p in LSeg(f/.i1,f/.(i1+1)) by A9,A11,A12,A13,TOPREAL1:def 5; i1 <= len f by A13,NAT_1:38; then i1 in Seg len f by A12,FINSEQ_1:3; then A15: i1 in dom f by FINSEQ_1:def 3; then A16: f is special by A1,JORDAN8:7,RELAT_1:60; 1 < i1+1 by A12,NAT_1:38; then i1+1 in Seg len f by A13,FINSEQ_1:3; then A17: i1+1 in dom f by FINSEQ_1:def 3; consider j0,i0 being Nat such that A18: [j0,i0] in Indices G & f/.i1 = G*(j0,i0) by A1,A15,GOBOARD1:def 11; consider jo,io being Nat such that A19: [jo,io] in Indices G & f/.(i1+1) = G*(jo,io) by A1,A17,GOBOARD1:def 11; A20: 1 <= j & j <= len G & 1 <= i & i <= width G by A3,GOBOARD5:1; A21: 1 <= k & k <= len G & 1 <= i & i <= width G by A3,GOBOARD5:1; A22: 1 <= j0 & j0 <= len G & 1 <= i0 & i0 <= width G by A18,GOBOARD5:1; A23: 1 <= jo & jo <= len G & 1 <= io & io <= width G by A19,GOBOARD5:1; A24: G*(j,i)`2 = G*(1,i)`2 by A20,GOBOARD5:2 .= G*(k,i)`2 by A21,GOBOARD5:2; A25: p in LSeg(G*(j,i),G*(k,i)) by A8,XBOOLE_0:def 3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A26: G*(j,i)`1 <= p`1 & p`1 <= G*(k,i)`1 by A25,TOPREAL1:9; ex n st j <= n & n <= k & G*(n,i) = p proof per cases by A12,A13,A16,TOPREAL1:def 7; suppose A27: (f/.i1)`2 = (f/.(i1+1))`2; G*(j,i0)`2 = G*(1,i0)`2 by A20,A22,GOBOARD5:2 .= G*(j0,i0)`2 by A22,GOBOARD5:2 .= p`2 by A14,A18,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; then A28: i0<=i & i0>=i by A20,A22,GOBOARD5:5; then A29: i=i0 by AXIOMS:21; G*(j,io)`2 = G*(1,io)`2 by A20,A23,GOBOARD5:2 .= G*(jo,io)`2 by A23,GOBOARD5:2 .= p`2 by A14,A19,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; then A30: io<=i & io>=i by A20,A23,GOBOARD5:5; then A31: i=io by AXIOMS:21; thus thesis proof per cases; suppose A32: (f/.i1)`1 <= (f/.(i1+1))`1; thus thesis proof per cases; suppose A33: (f/.(i1+1)) in LSeg(G*(j,i),G*(k,i)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.(i1+1) in L~f by A17,GOBOARD1:16; then f/.(i1+1) in X1 by A33,XBOOLE_0:def 3; then A34: p`1 >= (f/.(i1+1))`1 by A5,A7,PSCOMP_1:71; p`1 <= (f/.(i1+1))`1 by A14,A32,TOPREAL1:9; then A35: p`1 = (f/.(i1+1))`1 by A34,AXIOMS:21; take n=jo; A36: p in LSeg(G*(j,i),G*(k,i)) by A8,XBOOLE_0:def 3; then A37: p`2 = G*(j,i)`2 by A24,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A23,GOBOARD5:2; A38: p`1 = G*(jo,1)`1 by A19,A23,A35,GOBOARD5:3 .= G*(n,i)`1 by A20,A23,GOBOARD5:3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A39: G*(j,i)`1 <= G*(n,i)`1 & G*(n,i)`1 <= G*(k,i)`1 by A36,A38, TOPREAL1:9; hence j <= n by A20,A23,GOBOARD5:4; thus n <= k by A21,A23,A39,GOBOARD5:4; thus thesis by A37,A38,TOPREAL3:11; suppose A40: not f/.(i1+1) in LSeg(G*(j,i),G*(k,i)); A41: (f/.(i1+1))`2 = p`2 by A14,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; thus thesis proof per cases by A24,A40,A41,GOBOARD7:9; suppose A42: (f/.(i1+1))`1 > G*(k,i)`1; then A43: G*(jo,i)`1 > G*(k,i)`1 by A19,A30,AXIOMS:21; jo>=k by A19,A21,A23,A31,A42,GOBOARD5:4; then A44: jo>k by A43,AXIOMS:21; j0<=jo+0 by A18,A19,A22,A23,A29,A31,A32,GOBOARD5:4; then j0-jo <= 0 by REAL_1:86; then -(j0-jo) >= -0 by REAL_1:50; then A45: jo-j0 >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then abs(-(j0-jo)) = 1 by ABSVALUE:17; then abs(jo-j0) = 1 by XCMPLX_1:143; then jo-j0 = 1 by A45,ABSVALUE:def 1; then j0+jo-j0 = j0+1 by XCMPLX_1:29; then jo+(j0-j0) = j0+1 by XCMPLX_1:29; then j0+1=jo+0 by XCMPLX_1:14; then A46: j0>=k by A44,NAT_1:38; p`1 >= G*(j0,i0)`1 by A14,A18,A32,TOPREAL1:9; then p`1 >= G*(j0,1)`1 by A22,GOBOARD5:3; then p`1 >= G*(j0,i)`1 by A20,A22,GOBOARD5:3; then G*(k,i)`1 >= G*(j0,i)`1 by A26,AXIOMS:22; then k>=j0 by A21,A22,GOBOARD5:4; then A47: k=j0 by A46,AXIOMS:21; take n=j0; A48: p`2 = G*(j,i)`2 by A24,A25,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A22,GOBOARD5:2; p`1 >= G*(j0,i0)`1 by A14,A18,A32,TOPREAL1:9; then p`1 >= G*(j0,1)`1 by A22,GOBOARD5:3; then p`1 >= G*(j0,i)`1 by A20,A22,GOBOARD5:3; then p`1 = G*(k,i)`1 by A26,A47,AXIOMS:21; hence thesis by A4,A47,A48,TOPREAL3:11; suppose A49: (f/.(i1+1))`1 < G*(j,i)`1; p`1 <= (f/.(i1+1))`1 by A14,A32,TOPREAL1:9; hence thesis by A26,A49,AXIOMS:22; end; end; suppose A50: (f/.i1)`1 > (f/.(i1+1))`1; thus thesis proof per cases; suppose A51: f/.i1 in LSeg(G*(j,i),G*(k,i)); 1+1<=i1+1 by A12,AXIOMS:24; then 2<=len f by A13,AXIOMS:22; then f/.i1 in L~f by A15,GOBOARD1:16; then f/.i1 in X1 by A51,XBOOLE_0:def 3; then A52: p`1 >= (f/.i1)`1 by A5,A7,PSCOMP_1:71; p`1 <= (f/.i1)`1 by A14,A50,TOPREAL1:9; then A53: p`1 = (f/.i1)`1 by A52,AXIOMS:21; take n=j0; A54: p in LSeg(G*(j,i),G*(k,i)) by A8,XBOOLE_0:def 3; then A55: p`2 = G*(j,i)`2 by A24,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A22,GOBOARD5:2; A56: p`1 = G*(j0,1)`1 by A18,A22,A53,GOBOARD5:3 .= G*(n,i)`1 by A20,A22,GOBOARD5:3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A57: G*(j,i)`1 <= G*(n,i)`1 & G*(n,i)`1 <= G*(k,i)`1 by A54,A56, TOPREAL1:9; hence j <= n by A20,A22,GOBOARD5:4; thus n <= k by A21,A22,A57,GOBOARD5:4; thus thesis by A55,A56,TOPREAL3:11; suppose A58: not f/.i1 in LSeg(G*(j,i),G*(k,i)); A59: (f/.i1)`2 = p`2 by A14,A27,GOBOARD7:6 .= G*(j,i)`2 by A24,A25,GOBOARD7:6; thus thesis proof per cases by A24,A58,A59,GOBOARD7:9; suppose A60: (f/.i1)`1 > G*(k,i)`1; then A61: G*(j0,i)`1 > G*(k,i)`1 by A18,A28,AXIOMS:21; j0>=k by A18,A21,A22,A29,A60,GOBOARD5:4; then A62: j0>k by A61,AXIOMS:21; jo<=j0+0 by A18,A19,A22,A23,A29,A31,A50,GOBOARD5:4; then jo-j0 <= 0 by REAL_1:86; then -(jo-j0) >= -0 by REAL_1:50; then A63: j0-jo >= 0 by XCMPLX_1:143; abs(i0-io)+abs(j0-jo) = 1 by A1,A15,A17,A18,A19,GOBOARD1:def 11 ; then abs(0)+abs(j0-jo) = 1 by A29,A31,XCMPLX_1:14; then 0+abs(j0-jo) = 1 by ABSVALUE:7; then j0-jo = 1 by A63,ABSVALUE:def 1; then j0-(jo-jo) = jo+1 by XCMPLX_1:37; then jo+1=j0-0 by XCMPLX_1:14; then A64: jo>=k by A62,NAT_1:38; p`1 >= G*(jo,io)`1 by A14,A19,A50,TOPREAL1:9; then p`1 >= G*(jo,1)`1 by A23,GOBOARD5:3; then p`1 >= G*(jo,i)`1 by A20,A23,GOBOARD5:3; then G*(k,i)`1 >= G*(jo,i)`1 by A26,AXIOMS:22; then k>=jo by A21,A23,GOBOARD5:4; then A65: k=jo by A64,AXIOMS:21; take n=jo; A66: p`2 = G*(j,i)`2 by A24,A25,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A23,GOBOARD5:2; p`1 >= G*(jo,io)`1 by A14,A19,A50,TOPREAL1:9; then p`1 >= G*(jo,1)`1 by A23,GOBOARD5:3; then p`1 >= G*(jo,i)`1 by A20,A23,GOBOARD5:3; then p`1 = G*(k,i)`1 by A26,A65,AXIOMS:21; hence thesis by A4,A65,A66,TOPREAL3:11; suppose A67: (f/.i1)`1 < G*(j,i)`1; p`1 <= (f/.i1)`1 by A14,A50,TOPREAL1:9; hence thesis by A26,A67,AXIOMS:22; end; end; end; suppose (f/.i1)`1 = (f/.(i1+1))`1; then A68: p`1 = (f/.i1)`1 by A14,GOBOARD7:5; take n=j0; A69: p`2 = G*(j,i)`2 by A24,A25,GOBOARD7:6 .= G*(1,i)`2 by A20,GOBOARD5:2 .= G*(n,i)`2 by A20,A22,GOBOARD5:2; A70: p`1 = G*(j0,1)`1 by A18,A22,A68,GOBOARD5:3 .= G*(n,i)`1 by A20,A22,GOBOARD5:3; G*(j,i)`1 <= G*(k,i)`1 by A4,A20,A21,SPRECT_3:25; then A71: G*(j,i)`1 <= G*(n,i)`1 & G*(n,i)`1 <= G*(k,i)`1 by A25,A70,TOPREAL1: 9; hence j <= n by A20,A22,GOBOARD5:4; thus n <= k by A21,A22,A71,GOBOARD5:4; thus thesis by A69,A70,TOPREAL3:11; end; hence ex n st j <= n & n <= k & G*(n,i)`1 = sup(proj1.:X) by A7; end; theorem Th5: for C being compact non vertical non horizontal Subset of TOP-REAL 2 for n being Nat holds Upper_Seq(C,n)/.1 = W-min(L~Cage(C,n)) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; A1: Upper_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n) by JORDAN1E:def 1; A2: W-min L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:47; E-max L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:50; then E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A2,FINSEQ_6:96; then Upper_Seq(C,n)/.1 = Rotate(Cage(C,n),W-min L~Cage(C,n))/.1 by A1,FINSEQ_5:47; hence Upper_Seq(C,n)/.1 = W-min L~Cage(C,n) by A2,FINSEQ_6:98; end; theorem Th6: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds Lower_Seq(C,n)/.1 = E-max L~Cage(C,n) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by JORDAN1E:def 2; hence Lower_Seq(C,n)/.1 = E-max L~Cage(C,n) by FINSEQ_5:56; end; theorem Th7: for C being compact non vertical non horizontal Subset of TOP-REAL 2 for n being Nat holds Upper_Seq(C,n)/. len Upper_Seq(C,n) = E-max(L~Cage(C,n)) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; A1: Upper_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n) by JORDAN1E:def 1; W-min L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:47; then rng Rotate(Cage(C,n),W-min L~Cage(C,n)) = rng Cage(C,n) by FINSEQ_6:96 ; then A2: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by SPRECT_2:50; then len Upper_Seq(C,n) = (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) by A1,FINSEQ_5:45; hence Upper_Seq(C,n)/.len Upper_Seq(C,n) = E-max L~Cage(C,n) by A1,A2,FINSEQ_5:48; end; theorem Th8: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds Lower_Seq(C,n)/.(len Lower_Seq(C,n)) = W-min L~Cage(C,n) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; A1: Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by JORDAN1E:def 2; A2: W-min L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:47; E-max L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:50; then E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A2,FINSEQ_6:96; hence Lower_Seq(C,n)/.(len Lower_Seq(C,n)) = Rotate(Cage(C,n),W-min L~Cage(C,n))/. (len Rotate(Cage(C,n),W-min L~Cage(C,n))) by A1,FINSEQ_5:57 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/.1 by FINSEQ_6:def 1 .= W-min L~Cage(C,n) by A2,FINSEQ_6:98; end; theorem Th9: for C being compact non vertical non horizontal Subset of TOP-REAL 2 for n being Nat holds L~Upper_Seq(C,n) = Upper_Arc L~Cage(C,n) & L~Lower_Seq(C,n) = Lower_Arc L~Cage(C,n) or L~Upper_Seq(C,n) = Lower_Arc L~Cage(C,n) & L~Lower_Seq(C,n) = Upper_Arc L~Cage(C,n) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; set WC = W-min(L~Cage(C,n)); set EC = E-max(L~Cage(C,n)); A1: Upper_Seq(C,n)/.1 = WC by Th5; A2: Upper_Seq(C,n)/. len Upper_Seq(C,n) = EC by Th7; A3: Lower_Seq(C,n)/.1 = EC by Th6; A4: Lower_Seq(C,n)/. len Lower_Seq(C,n) = WC by Th8; A5: L~Upper_Seq(C,n) is_an_arc_of WC,EC by A1,A2,TOPREAL1:31; L~Lower_Seq(C,n) is_an_arc_of EC,WC by A3,A4,TOPREAL1:31; then A6: L~Lower_Seq(C,n) is_an_arc_of WC,EC by JORDAN5B:14; A7: L~Upper_Seq(C,n) \/ L~Lower_Seq(C,n)=L~Cage(C,n) by JORDAN1E:17; Upper_Arc(L~Cage(C,n)) is_an_arc_of WC,EC & Lower_Arc(L~Cage(C,n)) is_an_arc_of WC,EC & Upper_Arc(L~Cage(C,n)) \/ Lower_Arc(L~Cage(C,n))=L~Cage(C,n) & Upper_Arc(L~Cage(C,n)) /\ Lower_Arc(L~Cage(C,n))= {WC,EC} by JORDAN6:65; hence thesis by A5,A6,A7,JORDAN6:61; end; reserve C for compact non vertical non horizontal non empty being_simple_closed_curve Subset of TOP-REAL 2, p for Point of TOP-REAL 2, i1,j1,i2,j2 for Nat; theorem Th10: for C being connected compact non vertical non horizontal Subset of TOP-REAL 2 for n being Nat holds Upper_Seq(C,n) is_sequence_on Gauge(C,n) proof let C be connected compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; Cage(C,n) is_sequence_on Gauge(C,n) by JORDAN9:def 1; then A1: Rotate(Cage(C,n),W-min L~Cage(C,n)) is_sequence_on Gauge(C,n) by REVROT_1:34; Upper_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n) by JORDAN1E:def 1 .= Rotate(Cage(C,n),W-min L~Cage(C,n)) | ((E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) by FINSEQ_5:def 1; hence thesis by A1,GOBOARD1:38; end; theorem Th11: :: symmetric to JORDAN8:9 for f being FinSequence of TOP-REAL 2 st f is_sequence_on G & (ex i,j st [i,j] in Indices G & p = G*(i,j)) & (for i1,j1,i2,j2 st [i1,j1] in Indices G & [i2,j2] in Indices G & p = G*(i1,j1) & f/.1 = G*(i2,j2) holds abs(i2-i1)+abs(j2-j1) = 1) holds <*p*>^f is_sequence_on G proof let f be FinSequence of TOP-REAL 2 such that A1: f is_sequence_on G and A2: ex i,j st [i,j] in Indices G & p = G*(i,j) and A3: for i1,j1,i2,j2 st [i1,j1] in Indices G & [i2,j2] in Indices G & p = G*(i1,j1) & f/.1 = G*(i2,j2) holds abs(i2-i1)+abs(j2-j1) = 1; A4: for n st n in dom f & n+1 in dom f holds for m,k,i,j st [m,k] in Indices G & [i,j] in Indices G & f/.n=G*(m,k) & f/.(n+1)=G*(i,j) holds abs(m-i)+abs(k-j)=1 by A1,GOBOARD1:def 11; A5: now let n; assume n in dom <*p*> & n+1 in dom <*p*>; then 1 <= n & n+1 <= len <*p*> by FINSEQ_3:27; then 1+1 <= n+1 & n+1 <= 1 by AXIOMS:24,FINSEQ_1:56; hence for m,k,i,j st [m,k] in Indices G & [i,j] in Indices G & <*p*>/.n=G*(m,k) & <*p*>/.(n+1)=G*(i,j) holds abs(m-i)+abs(k-j)=1 by AXIOMS:22; end; now let m,k,i,j such that A6: [m,k] in Indices G & [i,j] in Indices G & <*p*>/.(len <*p*>)=G*(m,k) & f/.1=G*(i,j) and A7: len <*p*> in dom <*p*> & 1 in dom f; len <*p*> = 1 by FINSEQ_1:57; then <*p*>.(len <*p*>) = p by FINSEQ_1:57; then <*p*>/.(len <*p*>) = p by A7,FINSEQ_4:def 4; then abs(i-m)+abs(j-k)=1 by A3,A6; hence 1 = abs(m-i)+abs(j-k) by UNIFORM1:13 .= abs(m-i)+abs(k-j) by UNIFORM1:13; end; then A8: for n st n in dom(<*p*>^f) & n+1 in dom(<*p*>^f) holds for m,k,i,j st [m,k] in Indices G & [i,j] in Indices G & (<*p*>^f)/.n =G*(m,k) & (<*p*>^f)/.(n+1)=G*(i,j) holds abs(m-i)+abs(k-j)=1 by A4,A5,GOBOARD1:40; now let n such that A9: n in dom(<*p*>^f); per cases by A9,FINSEQ_1:38; suppose A10: n in dom <*p*>; then n in Seg 1 by FINSEQ_1:55; then 1 <= n & n <= 1 by FINSEQ_1:3; then n=1 by AXIOMS:21; then <*p*>.n = p by FINSEQ_1:57; then A11: <*p*>/.n = p by A10,FINSEQ_4:def 4; consider i,j such that A12: [i,j] in Indices G and A13: p = G*(i,j) by A2; take i,j; thus [i,j] in Indices G by A12; thus (<*p*>^f)/.n = G*(i,j) by A10,A11,A13,GROUP_5:95; suppose ex l st l in dom f & n = (len <*p*>) + l; then consider l such that A14: l in dom f and A15: n = (len <*p*>) + l; consider i,j such that A16: [i,j] in Indices G and A17: f/.l = G*(i,j) by A1,A14,GOBOARD1:def 11; take i,j; thus [i,j] in Indices G by A16; thus (<*p*>^f)/.n = G*(i,j) by A14,A15,A17,GROUP_5:96; end; hence <*p*>^f is_sequence_on G by A8,GOBOARD1:def 11; end; theorem Th12: for C being connected compact non vertical non horizontal Subset of TOP-REAL 2 for n being Nat holds Lower_Seq(C,n) is_sequence_on Gauge(C,n) proof let C be connected compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; A1: Cage(C,n) is_sequence_on Gauge(C,n) by JORDAN9:def 1; then Rotate(Cage(C,n),W-min L~Cage(C,n)) is_sequence_on Gauge(C,n) by REVROT_1:34; then A2: (Rotate(Cage(C,n),W-min L~Cage(C,n))/^ (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) is_sequence_on Gauge(C,n) by JORDAN8:5; consider j such that A3: 1 <= j & j <= width Gauge(C,n) & E-max L~Cage(C,n)=Gauge(C,n)*(len Gauge(C,n),j) by JORDAN1D:29; set i = len Gauge(C,n); i >=4 by JORDAN8:13; then 1<=i by AXIOMS:22; then A4: [i,j] in Indices Gauge(C,n) by A3,GOBOARD7:10; set E1 = ((Rotate(Cage(C,n),W-min L~Cage(C,n))/^ (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))))/.1; A5: for i1,j1,i2,j2 st [i1,j1] in Indices Gauge(C,n) & [i2,j2] in Indices Gauge(C,n) & E-max L~Cage(C,n) = Gauge(C,n)*(i1,j1) & E1 = Gauge(C,n)*(i2,j2) holds abs(i2-i1)+abs(j2-j1) = 1 proof let i1,j1,i2,j2; assume that A6: [i1,j1] in Indices Gauge(C,n) and A7: [i2,j2] in Indices Gauge(C,n) and A8: E-max L~Cage(C,n) = Gauge(C,n)*(i1,j1) and A9: E1 = Gauge(C,n)*(i2,j2); set en = (E-max L~Cage(C,n))..Cage(C,n); A10: E-max L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:50; A11: W-min L~Cage(C,n) in rng Cage(C,n) by SPRECT_2:47; A12: Cage(C,n)/.1 = N-min L~Cage(C,n) by JORDAN9:34; then A13: (E-max L~Cage(C,n))..Cage(C,n) < (E-min L~Cage(C,n))..Cage(C,n) by SPRECT_2:75; (E-min L~Cage(C,n))..Cage(C,n) <= (S-max L~Cage(C,n))..Cage(C,n) by A12,SPRECT_2:76; then A14: (E-max L~Cage(C,n))..Cage(C,n) < (S-max L~Cage(C,n))..Cage(C,n) by A13,AXIOMS:22; (S-max L~Cage(C,n))..Cage(C,n) < (S-min L~Cage(C,n))..Cage(C,n) by A12,SPRECT_2:77; then A15: (E-max L~Cage(C,n))..Cage(C,n) < (S-min L~Cage(C,n))..Cage(C,n) by A14,AXIOMS:22; (S-min L~Cage(C,n))..Cage(C,n) <= (W-min L~Cage(C,n))..Cage(C,n) by A12,SPRECT_2:78; then A16: (E-max L~Cage(C,n))..Cage(C,n) < (W-min L~Cage(C,n))..Cage(C,n) by A15,AXIOMS:22; A17: E-max L~Cage(C,n)=Cage(C,n)/.en by A10,FINSEQ_5:41; A18: en in dom Cage(C,n) by A10,FINSEQ_4:30; A19: 1<=en+1 by NAT_1:29; en < len Cage(C,n) by SPRECT_5:17; then en+1 <= len Cage(C,n) by NAT_1:38; then A20: en+1 in dom Cage(C,n) by A19,FINSEQ_3:27; 1 <= (E-max L~Cage(C,n))..Cage(C,n) by A10,FINSEQ_4:31; then A21: 1 < (E-max L~Cage(C,n))..Cage(C,n)+1 by NAT_1:38; A22: (E-max L~Cage(C,n))..Cage(C,n)+1 <= (W-min L~Cage(C,n))..Cage(C,n) by A16,NAT_1:38; (W-min L~Cage(C,n))..Cage(C,n) < len Cage(C,n) by SPRECT_5:21; then A23: len Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n) > 0 by SQUARE_1:11; (E-max L~Cage(C,n))..Cage(C,n) + 1 >= 0 by NAT_1:18; then ((E-max L~Cage(C,n))..Cage(C,n) + 1 + (len Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n))) >= 0+0 by A23,REAL_1:67; then A24: ((E-max L~Cage(C,n))..Cage(C,n) + 1 + len Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n)) >= 0 by XCMPLX_1:29; E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A10,A11,FINSEQ_6:96; then A25: 1 <= (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) & (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) <= len Rotate(Cage(C,n),W-min L~Cage(C,n)) by FINSEQ_4:31; now assume (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) = len (Rotate(Cage(C,n),W-min L~Cage(C,n))); then (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) = len Cage(C,n) by REVROT_1:14; then len Upper_Seq(C,n) = len Cage(C,n) by JORDAN1E:12; then len Cage(C,n) + len Lower_Seq(C,n) = len Cage(C,n)+1 by JORDAN1E:14 ; then len Lower_Seq(C,n) = 1 by XCMPLX_1:2; hence contradiction by JORDAN1E:19; end; then (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) < len (Rotate(Cage(C,n),W-min L~Cage(C,n))) by A25,AXIOMS:21; then (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) + 1 <= len (Rotate(Cage(C,n),W-min L~Cage(C,n))) by NAT_1:38; then 1 + (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) - (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) <= len (Rotate(Cage(C,n),W-min L~Cage(C,n))) - (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) by REAL_1:49; then 1 <= len (Rotate(Cage(C,n),W-min L~Cage(C,n))) - ((E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) by XCMPLX_1:26; then 1 <= len (Rotate(Cage(C,n),W-min L~Cage(C,n))/^ (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) by A25,RFINSEQ:def 2; then 1 in dom (Rotate(Cage(C,n),W-min L~Cage(C,n))/^ (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) by FINSEQ_3:27; then E1 = Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))+1) by FINSEQ_5:30 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. (len Cage(C,n) + (E-max L~Cage(C,n))..Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n)+1) by A10,A11,A16,SPRECT_5:10 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Cage(C,n)+ (len Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n))+1) by XCMPLX_1:29 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Cage(C,n)+ (len Cage(C,n) -' (W-min L~Cage(C,n))..Cage(C,n))+1) by A23,BINARITH:def 3 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Cage(C,n)+1+ (len Cage(C,n) -'(W-min L~Cage(C,n))..Cage(C,n))) by XCMPLX_1:1 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Cage(C,n)+1+ (len Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n))) by A23,BINARITH:def 3 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Cage(C,n)+1+ len Cage(C,n) - (W-min L~Cage(C,n))..Cage(C,n)) by XCMPLX_1:29 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. ((E-max L~Cage(C,n))..Cage(C,n)+1+ len Cage(C,n) -' (W-min L~Cage(C,n))..Cage(C,n)) by A24,BINARITH:def 3; then E1=Cage(C,n)/.(en+1) by A11,A21,A22,REVROT_1:13; then abs(i1-i2)+abs(j1-j2) = 1 by A1,A6,A7,A8,A9,A17,A18,A20,GOBOARD1:def 11; then abs(i1-i2)+abs(j2-j1) = 1 by UNIFORM1:13; hence abs(i2-i1)+abs(j2-j1) = 1 by UNIFORM1:13; end; Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by JORDAN1E:def 2 .= <*E-max L~Cage(C,n)*>^(Rotate(Cage(C,n),W-min L~Cage(C,n))/^ (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) by FINSEQ_5:def 2; hence thesis by A2,A3,A4,A5,Th11; end; theorem p`1 = (W-bound C + E-bound C)/2 & p`2 = inf(proj2.:(LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ Upper_Arc L~Cage(C,i+1))) implies ex j st 1 <= j & j <= width Gauge(C,i+1) & p = Gauge(C,i+1)*(Center Gauge(C,i+1),j) proof assume that A1: p`1 = (W-bound C + E-bound C)/2 and A2: p`2 = inf(proj2.:(LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ Upper_Arc L~Cage(C,i+1))); per cases by Th9; suppose A3: L~Upper_Seq(C,i+1) = Upper_Arc L~Cage(C,i+1) & L~Lower_Seq(C,i+1) = Lower_Arc L~Cage(C,i+1); set f = Upper_Seq (C,i+1); set G = Gauge(C,i+1); set l = Center Gauge(C,i+1); set k = width Gauge(C,i+1); A4: width Gauge(C,i+1) = len Gauge(C,i+1) & width Gauge(C,1) = len Gauge(C,1) by JORDAN8:def 1; A5: f is_sequence_on G by Th10; k >= 4 by A4,JORDAN8:13; then A6: 1 <= k by AXIOMS:22; then A7: l <= len G by A4,JORDAN1B:13; width Gauge(C,1) >= 4 by A4,JORDAN8:13; then A8: 1 <= width Gauge(C,1) by AXIOMS:22; then A9: Center Gauge(C,1) <= len Gauge(C,1) by A4,JORDAN1B:13; A10: 1 <= l by JORDAN1B:12; A11: 1 <= Center Gauge(C,1) by JORDAN1B:12; A12: LSeg(G*(l,1),G*(l,k)) meets L~f by A3,A4,A7,A10,JORDAN1B:32; A13: [l,1] in Indices G by A6,A7,A10,GOBOARD7:10; [l,k] in Indices G by A6,A7,A10,GOBOARD7:10; then consider n such that A14: 1 <= n & n <= k and A15: G*(l,n)`2 = inf(proj2.:(LSeg(G*(l,1),G*(l,k)) /\ L~f)) by A5,A6,A12,A13, Th1; take n; thus 1 <= n & n <= width Gauge(C,i+1) by A14; A16: i+1 > 0 & 1 > 0 by NAT_1:19; len Gauge(C,1) >= 4 by JORDAN8:13; then A17: 1 <= len Gauge(C,1) by AXIOMS:22; then A18: p`1 = (Gauge(C,1)*(Center Gauge(C,1),1))`1 by A1,JORDAN1A:59 .= Gauge(C,i+1)*(Center Gauge(C,i+1),n)`1 by A4,A14,A16,A17,JORDAN1A:57; 1 <= i+1 by NAT_1:29; then A19: LSeg(G*(l,1),G*(l,k)) c= LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) by A4,JORDAN1A:65; LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ L~f = LSeg(G*(l,1),G*(l,k)) /\ L~f proof thus LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ L~f c= LSeg(G*(l,1),G*(l,k)) /\ L~f proof let a be set; assume A20: a in LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ L~f; then reconsider a1=a as Point of TOP-REAL 2; A21: a1 in LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) & a1 in L~f by A20,XBOOLE_0:def 3; Gauge(C,1)*(Center Gauge(C,1),1)`1 = Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))`1 by A8,A9,A11,GOBOARD5:3; then A22: a1`1 = Gauge(C,1)*(Center Gauge(C,1),1)`1 by A21,GOBOARD7:5 .= G*(l,1)`1 by A4,A6,A8,A16,JORDAN1A:57; then A23: a1`1 = G*(l,k)`1 by A6,A7,A10,GOBOARD5:3; Cage(C,i+1) is_sequence_on G by JORDAN9:def 1; then A24: G*(l,1)`2 <= S-bound L~Cage(C,i+1) by A7,A10,JORDAN1A:43; A25: Upper_Arc L~Cage(C,i+1) c= L~Cage(C,i+1) by JORDAN1A:16; a1 in Upper_Arc L~Cage(C,i+1) by A3,A20,XBOOLE_0:def 3; then a1`2 >= S-bound L~Cage(C,i+1) by A25,PSCOMP_1:71; then A26: a1`2 >= G*(l,1)`2 by A24,AXIOMS:22; Cage(C,i+1) is_sequence_on G by JORDAN9:def 1; then A27: G*(l,k)`2 >= N-bound L~Cage(C,i+1) by A7,A10,JORDAN1A:41; a1 in Upper_Arc L~Cage(C,i+1) by A3,A20,XBOOLE_0:def 3; then a1`2 <= N-bound L~Cage(C,i+1) by A25,PSCOMP_1:71; then a1`2 <= G*(l,k)`2 by A27,AXIOMS:22; then a1 in LSeg(G*(l,1),G*(l,k)) by A22,A23,A26,GOBOARD7:8; hence a in LSeg(G*(l,1),G*(l,k)) /\ L~f by A21,XBOOLE_0:def 3; end; thus thesis by A19,XBOOLE_1:26; end; hence p = Gauge(C,i+1)*(Center Gauge(C,i+1),n) by A2,A3,A15,A18,TOPREAL3:11 ; suppose A28: L~Upper_Seq(C,i+1) = Lower_Arc L~Cage(C,i+1) & L~Lower_Seq(C,i+1) = Upper_Arc L~Cage(C,i+1); set f = Lower_Seq (C,i+1); set G = Gauge(C,i+1); set l = Center Gauge(C,i+1); set k = width Gauge(C,i+1); A29: width Gauge(C,i+1) = len Gauge(C,i+1) & width Gauge(C,1) = len Gauge(C,1) by JORDAN8:def 1; A30: f is_sequence_on G by Th12; k >= 4 by A29,JORDAN8:13; then A31: 1 <= k by AXIOMS:22; then A32: l <= len G by A29,JORDAN1B:13; width Gauge(C,1) >= 4 by A29,JORDAN8:13; then A33: 1 <= width Gauge(C,1) by AXIOMS:22; then A34: Center Gauge(C,1) <= len Gauge(C,1) by A29,JORDAN1B:13; A35: 1 <= l by JORDAN1B:12; A36: 1 <= Center Gauge(C,1) by JORDAN1B:12; A37: LSeg(G*(l,1),G*(l,k)) meets L~f by A28,A29,A32,A35,JORDAN1B:32; A38: [l,1] in Indices G by A31,A32,A35,GOBOARD7:10; [l,k] in Indices G by A31,A32,A35,GOBOARD7:10; then consider n such that A39: 1 <= n & n <= k and A40: G*(l,n)`2 = inf(proj2.:(LSeg(G*(l,1),G*(l,k)) /\ L~f)) by A30,A31,A37,A38, Th1; take n; thus 1 <= n & n <= width Gauge(C,i+1) by A39; A41: i+1 > 0 & 1 > 0 by NAT_1:19; len Gauge(C,1) >= 4 by JORDAN8:13; then A42: 1 <= len Gauge(C,1) by AXIOMS:22; then A43: p`1 = (Gauge(C,1)*(Center Gauge(C,1),1))`1 by A1,JORDAN1A:59 .= Gauge(C,i+1)*(Center Gauge(C,i+1),n)`1 by A29,A39,A41,A42,JORDAN1A:57 ; 1 <= i+1 by NAT_1:29; then A44: LSeg(G*(l,1),G*(l,k)) c= LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) by A29,JORDAN1A:65; LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ L~f = LSeg(G*(l,1),G*(l,k)) /\ L~f proof thus LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ L~f c= LSeg(G*(l,1),G*(l,k)) /\ L~f proof let a be set; assume A45: a in LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) /\ L~f; then reconsider a1=a as Point of TOP-REAL 2; A46: a1 in LSeg(Gauge(C,1)*(Center Gauge(C,1),1), Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))) & a1 in L~f by A45,XBOOLE_0:def 3; Gauge(C,1)*(Center Gauge(C,1),1)`1 = Gauge(C,1)*(Center Gauge(C,1),width Gauge(C,1))`1 by A33,A34,A36,GOBOARD5:3; then A47: a1`1 = Gauge(C,1)*(Center Gauge(C,1),1)`1 by A46,GOBOARD7:5 .= G*(l,1)`1 by A29,A31,A33,A41,JORDAN1A:57; then A48: a1`1 = G*(l,k)`1 by A31,A32,A35,GOBOARD5:3; Cage(C,i+1) is_sequence_on G by JORDAN9:def 1; then A49: G*(l,1)`2 <= S-bound L~Cage(C,i+1) by A32,A35,JORDAN1A:43; A50: Upper_Arc L~Cage(C,i+1) c= L~Cage(C,i+1) by JORDAN1A:16; a1 in Upper_Arc L~Cage(C,i+1) by A28,A45,XBOOLE_0:def 3; then a1`2 >= S-bound L~Cage(C,i+1) by A50,PSCOMP_1:71; then A51: a1`2 >= G*(l,1)`2 by A49,AXIOMS:22; Cage(C,i+1) is_sequence_on G by JORDAN9:def 1; then A52: G*(l,k)`2 >= N-bound L~Cage(C,i+1) by A32,A35,JORDAN1A:41; a1 in Upper_Arc L~Cage(C,i+1) by A28,A45,XBOOLE_0:def 3; then a1`2 <= N-bound L~Cage(C,i+1) by A50,PSCOMP_1:71; then a1`2 <= G*(l,k)`2 by A52,AXIOMS:22; then a1 in LSeg(G*(l,1),G*(l,k)) by A47,A48,A51,GOBOARD7:8; hence a in LSeg(G*(l,1),G*(l,k)) /\ L~f by A46,XBOOLE_0:def 3; end; thus thesis by A44,XBOOLE_1:26; end; hence p = Gauge(C,i+1)*(Center Gauge(C,i+1),n) by A2,A28,A40,A43,TOPREAL3:11 ; end;