Copyright (c) 2001 Association of Mizar Users
environ vocabulary EUCLID, COMPTS_1, PSCOMP_1, ORDINAL2, FUNCT_5, REALSET1, FINSEQ_1, SPRECT_2, RELAT_1, FINSEQ_5, FINSEQ_4, ARYTM_1, PRE_TOPC, TOPREAL1, JORDAN3, BOOLE, GROUP_2, FUNCT_1, SPPOL_1, FINSEQ_6, JORDAN9, GRAPH_2, TOPREAL2, CARD_1, RELAT_2, MCART_1, GOBOARD1, JORDAN8, MATRIX_1, TREES_1, JORDAN1E; notation TARSKI, XBOOLE_0, ENUMSET1, XCMPLX_0, XREAL_0, NAT_1, FUNCT_1, FINSEQ_1, FINSEQ_4, FINSEQ_5, MATRIX_1, FINSEQ_6, STRUCT_0, GRAPH_2, PRE_TOPC, TOPREAL2, CARD_1, BINARITH, CONNSP_1, COMPTS_1, EUCLID, PSCOMP_1, SPRECT_2, GOBOARD1, TOPREAL1, SPPOL_1, JORDAN3, JORDAN8, JORDAN9; constructors JORDAN8, REALSET1, REAL_1, CARD_4, PSCOMP_1, BINARITH, CONNSP_1, JORDAN9, FINSEQ_4, GOBRD13, JORDAN3, TOPREAL2, FINSEQ_5, ENUMSET1, FINSOP_1, GRAPH_2, PARTFUN1; clusters XREAL_0, SPRECT_1, TOPREAL6, JORDAN8, REVROT_1, RELSET_1, ARYTM_3, PSCOMP_1, SPRECT_3, FINSEQ_5, SPPOL_2, JORDAN1A, GOBOARD4, JORDAN1B, MEMBERED; requirements NUMERALS, BOOLE, SUBSET, REAL, ARITHM; definitions TARSKI, TOPREAL1, SPRECT_2, XBOOLE_0; theorems AXIOMS, BINARITH, JORDAN8, PSCOMP_1, JORDAN1A, NAT_1, REAL_1, GOBOARD5, REAL_2, FINSEQ_1, FINSEQ_2, SPRECT_2, FINSEQ_4, FINSEQ_5, FINSEQ_6, GOBOARD7, SPPOL_2, REVROT_1, TOPREAL1, SPRECT_3, JORDAN5B, AMI_5, JORDAN3, JORDAN9, GOBOARD1, TARSKI, FINSEQ_3, FUNCT_1, TOPREAL5, JORDAN10, GRAPH_2, CARD_1, CARD_2, YELLOW_6, PRE_CIRC, ENUMSET1, JORDAN1B, SPRECT_5, SCMFSA_7, XBOOLE_0, XBOOLE_1, XCMPLX_0, XCMPLX_1; begin :: Preliminaries reserve n for Nat; theorem for X be non empty Subset of TOP-REAL 2 for Y be compact Subset of TOP-REAL 2 st X c= Y holds N-bound X <= N-bound Y proof let X be non empty Subset of TOP-REAL 2; let Y be compact Subset of TOP-REAL 2; assume X c= Y; then sup (proj2||X) <= sup (proj2||Y) by PSCOMP_1:63; then sup (proj2||X) <= N-bound Y by PSCOMP_1:def 31; hence N-bound X <= N-bound Y by PSCOMP_1:def 31; end; theorem for X be non empty Subset of TOP-REAL 2 for Y be compact Subset of TOP-REAL 2 st X c= Y holds E-bound X <= E-bound Y proof let X be non empty Subset of TOP-REAL 2; let Y be compact Subset of TOP-REAL 2; assume X c= Y; then sup (proj1||X) <= sup (proj1||Y) by PSCOMP_1:63; then sup (proj1||X) <= E-bound Y by PSCOMP_1:def 32; hence E-bound X <= E-bound Y by PSCOMP_1:def 32; end; theorem for X be non empty Subset of TOP-REAL 2 for Y be compact Subset of TOP-REAL 2 st X c= Y holds S-bound X >= S-bound Y proof let X be non empty Subset of TOP-REAL 2; let Y be compact Subset of TOP-REAL 2; assume X c= Y; then inf (proj2||X) >= inf (proj2||Y) by PSCOMP_1:62; then inf (proj2||X) >= S-bound Y by PSCOMP_1:def 33; hence S-bound X >= S-bound Y by PSCOMP_1:def 33; end; theorem for X be non empty Subset of TOP-REAL 2 for Y be compact Subset of TOP-REAL 2 st X c= Y holds W-bound X >= W-bound Y proof let X be non empty Subset of TOP-REAL 2; let Y be compact Subset of TOP-REAL 2; assume X c= Y; then inf (proj1||X) >= inf (proj1||Y) by PSCOMP_1:62; then inf (proj1||X) >= W-bound Y by PSCOMP_1:def 30; hence W-bound X >= W-bound Y by PSCOMP_1:def 30; end; theorem Th5: for f,g be FinSequence of TOP-REAL 2 st f is_in_the_area_of g for p be Element of TOP-REAL 2 st p in rng f holds f-:p is_in_the_area_of g proof let f,g be FinSequence of TOP-REAL 2; assume A1: f is_in_the_area_of g; let p be Element of TOP-REAL 2; assume A2: p in rng f; let n be Nat; assume A3: n in dom(f-:p); A4: p..f <= len f by A2,FINSEQ_4:31; A5: len(f-:p) = p..f by A2,FINSEQ_5:45; then n in Seg(p..f) by A3,FINSEQ_1:def 3; then A6: (f-:p)/.n = f/.n by A2,FINSEQ_5:46; n in Seg len(f-:p) by A3,FINSEQ_1:def 3; then 1 <= n & n <= p..f by A5,FINSEQ_1:3; then 1 <= n & n <= len f by A4,AXIOMS:22; then n in dom f by FINSEQ_3:27; hence thesis by A1,A6,SPRECT_2:def 1; end; theorem Th6: for f,g be FinSequence of TOP-REAL 2 st f is_in_the_area_of g for p be Element of TOP-REAL 2 st p in rng f holds f:-p is_in_the_area_of g proof let f,g be FinSequence of TOP-REAL 2; assume A1: f is_in_the_area_of g; let p be Element of TOP-REAL 2; assume A2: p in rng f; let n be Nat; assume A3: n in dom(f:-p); A4: len(f:-p) = len f - p..f + 1 by A2,FINSEQ_5:53; n in Seg len(f:-p) by A3,FINSEQ_1:def 3; then A5: 0+1 <= n & n <= len f - p..f + 1 by A4,FINSEQ_1:3; A6: n-'1 >= 0 by NAT_1:18; 1 <= p..f by A2,FINSEQ_4:31; then A7: 0+1 <= n-'1+p..f by A6,REAL_1:55; A8: n-1 >= 0 by A5,REAL_1:84; n - 1 <= len f - p..f by A5,REAL_1:86; then n - 1 + p..f <= len f by REAL_1:84; then n-'1+p..f <= len f by A8,BINARITH:def 3; then A9: n-'1+p..f in dom f by A7,FINSEQ_3:27; n-'1+1 = n by A5,AMI_5:4; then (f:-p)/.n = f/.(n-'1+p..f) by A2,A3,FINSEQ_5:55; hence thesis by A1,A9,SPRECT_2:def 1; end; theorem for f be non empty FinSequence of TOP-REAL 2 for p be Point of TOP-REAL 2 st p in L~f holds L_Cut (f,p) <> {} proof let f be non empty FinSequence of TOP-REAL 2; let p be Point of TOP-REAL 2; assume that A1: p in L~f and A2: L_Cut (f,p) = {}; <*p*>^mid(f,Index(p,f)+1,len f) is non empty & (p<>f.(Index(p,f)+1) or p=f.(Index(p,f)+1)); then A3: L_Cut(f,p) = mid(f,Index(p,f)+1,len f) & p=f.(Index(p,f)+1) by A2,JORDAN3:def 4; len f in dom f by SCMFSA_7:12; then not Index(p,f)+1 in dom f by A2,A3,SPRECT_2:11; then not Index(p,f)+1 in Seg len f by FINSEQ_1:def 3; then Index(p,f)+1 < 1 or Index(p,f)+1 > len f by FINSEQ_1:3; then Index(p,f) >= len f by NAT_1:29,38; hence contradiction by A1,JORDAN3:41; end; theorem for f be non empty FinSequence of TOP-REAL 2 for p be Point of TOP-REAL 2 st p in L~f & len R_Cut(f,p) >= 2 holds f.1 in L~R_Cut(f,p) proof let f be non empty FinSequence of TOP-REAL 2; let p be Point of TOP-REAL 2; len f <> 0 by FINSEQ_1:25; then len f > 0 by NAT_1:19; then A1: 0+1 <= len f by NAT_1:38; assume p in L~f; then A2: R_Cut(f,p).1 = f.1 by A1,JORDAN1B:4; assume 2 <= len R_Cut(f,p); hence f.1 in L~R_Cut(f,p) by A2,JORDAN3:34; end; theorem Th9: for f be non empty FinSequence of TOP-REAL 2 st f is_S-Seq for p be Point of TOP-REAL 2 st p in L~f holds not f.1 in L~mid(f,Index(p,f)+1,len f) proof let f be non empty FinSequence of TOP-REAL 2 such that A1: f is_S-Seq; let p be Point of TOP-REAL 2 such that A2: p in L~f and A3: f.1 in L~mid(f,Index(p,f)+1,len f); A4: 1 <= Index(p,f)+1 by NAT_1:29; Index(p,f) < len f by A2,JORDAN3:41; then A5: Index(p,f)+1 <= len f by NAT_1:38; 1 in dom f by FINSEQ_5:6; then f/.1 in L~mid(f,Index(p,f)+1,len f) by A3,FINSEQ_4:def 4; then Index(p,f)+1 = 0+1 by A1,A4,A5,JORDAN5B:16; then Index(p,f) = 0 by XCMPLX_1:2; hence contradiction by A2,JORDAN3:41; end; theorem Th10: for i,j,m,n be Nat holds i+j = m+n & i <= m & j <= n implies i = m proof let i,j,m,n be Nat; assume that A1: i+j = m+n and A2: i <= m and A3: j <= n; consider k be Nat such that A4: m = i + k by A2,NAT_1:28; consider l be Nat such that A5: n = j + l by A3,NAT_1:28; i+(k+n) = i+j by A1,A4,XCMPLX_1:1; then k+n = j by XCMPLX_1:2; then j + (l+k) = j+0 by A5,XCMPLX_1:1; then l+k = 0 by XCMPLX_1:2; then k = 0 by NAT_1:23; hence i = m by A4; end; theorem for f be non empty FinSequence of TOP-REAL 2 st f is_S-Seq for p be Point of TOP-REAL 2 st p in L~f & f.1 in L~L_Cut(f,p) holds f.1 = p proof let f be non empty FinSequence of TOP-REAL 2; assume A1: f is_S-Seq; then A2:f is one-to-one unfolded s.n.c. special & len f >= 2 by TOPREAL1:def 10 ; let p be Point of TOP-REAL 2 such that A3: p in L~f and A4: f.1 in L~L_Cut(f,p) and A5: f.1 <> p; set g = mid(f,Index(p,f)+1,len f); A6: len f in dom f by FINSEQ_5:6; 1 in dom f by FINSEQ_5:6; then A7: f/.1 = f.1 by FINSEQ_4:def 4; A8: not f.1 in L~g by A1,A3,Th9; then p<>f.(Index(p,f)+1) by A4,JORDAN3:def 4; then A9: L_Cut(f,p) = <*p*>^g by JORDAN3:def 4; per cases; suppose g is empty; then L_Cut(f,p) = <*p*> by A9,FINSEQ_1:47; then len L_Cut(f,p) = 1 by FINSEQ_1:56; hence contradiction by A4,TOPREAL1:28; suppose g is non empty; then L~L_Cut(f,p) = LSeg(p,g/.1) \/ L~g by A9,SPPOL_2:20; then A10: f.1 in LSeg(p,g/.1) by A4,A8,XBOOLE_0:def 2; consider i being Nat such that A11: 1 <= i & i+1 <= len(<*p*>^g) and A12: f/.1 in LSeg(<*p*>^g,i) by A4,A7,A9,SPPOL_2:13; A13: 1 <= Index(p,f) by A3,JORDAN3:41; LSeg(<*p*>^g,i) c= LSeg(f,Index(p,f)+i-'1) by A3,A11,JORDAN3:49; then A14: Index(p,f)+i-'1 = 1 by A2,A12,JORDAN5B:33; 1+1 <= Index(p,f)+i by A11,A13,REAL_1:55; then 1 <= Index(p,f)+i by AXIOMS:22; then A15: Index(p,f)+i = 1+1 by A14,AMI_5:4; then Index(p,f) = 1 by A11,A13,Th10; then A16: p in LSeg(f,1) by A3,JORDAN3:42; A17: i = 1 by A11,A13,A15,Th10; A18: 1+1 <= len f by A1,TOPREAL1:def 10; then A19: p in LSeg(f/.1,f/.(1+1)) by A16,TOPREAL1:def 5; 2 in dom f by A18,FINSEQ_3:27; then g/.1 = f/.(1+1) by A6,A15,A17,SPRECT_2:12; hence contradiction by A5,A7,A10,A19,SPRECT_3:16; end; begin :: About Upper and Lower Sequence of a Cage definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; func Upper_Seq(C,n) -> FinSequence of TOP-REAL 2 equals :Def1: Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n); coherence; end; theorem Th12: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds len Upper_Seq(C,n) = (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) proof let C be compact non vertical non horizontal non empty Subset of TOP-REAL 2; let n be Nat; A1: 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 A2: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A1,FINSEQ_6:96; thus len Upper_Seq(C,n) = len (Rotate(Cage(C,n),W-min L~Cage(C,n))-:(E-max L~Cage(C,n))) by Def1 .= (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) by A2,FINSEQ_5:45; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; func Lower_Seq(C,n) -> FinSequence of TOP-REAL 2 equals :Def2: Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n); coherence; end; theorem Th13: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds len Lower_Seq(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))+1 proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; A1: 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 A2: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A1,FINSEQ_6:96; thus len Lower_Seq(C,n) = len (Rotate(Cage(C,n),W-min L~Cage(C,n)):-(E-max L~Cage(C,n))) by Def2 .= 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))+1 by A2,FINSEQ_5:53; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; cluster Upper_Seq(C,n) -> non empty; coherence proof A1: 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 A2: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A1,FINSEQ_6:96; len Upper_Seq(C,n) = (E-max L~Cage(C,n))..Rotate(Cage(C,n), W-min L~Cage(C,n)) by Th12; then len Upper_Seq(C,n) >= 0+1 by A2,FINSEQ_4:31; then len Upper_Seq(C,n) > 0 by NAT_1:38; hence thesis by FINSEQ_1:25; end; cluster Lower_Seq(C,n) -> non empty; coherence proof A3: 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 A4: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A3,FINSEQ_6:96; len Lower_Seq(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))+1 by Th13; then len Lower_Seq(C,n)-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 .= 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_0:def 8 ; then len Lower_Seq(C,n)-1+(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 XCMPLX_1: 139; 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))-(len Lower_Seq(C,n)-1) by XCMPLX_1:26 .= len Rotate(Cage(C,n),W-min L~Cage(C,n))-len Lower_Seq(C,n)+1 by XCMPLX_1:37; then len Rotate(Cage(C,n),W-min L~Cage(C,n))-len Lower_Seq(C,n)+1 <= len Rotate(Cage(C,n),W-min L~Cage(C,n)) by A4,FINSEQ_4:31; then len Rotate(Cage(C,n),W-min L~Cage(C,n))-len Lower_Seq(C,n) <= len Rotate(Cage(C,n),W-min L~Cage(C,n))-1 by REAL_1:84; then len Lower_Seq(C,n) >= 0+1 by REAL_2:105; then len Lower_Seq(C,n) > 0 by NAT_1:38; hence thesis by FINSEQ_1:25; end; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; cluster Upper_Seq(C,n) -> one-to-one special unfolded s.n.c.; coherence proof A1: Upper_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n) by Def1; set f = Rotate(Cage(C,n),W-min L~Cage(C,n)); 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 A3: E-max L~Cage(C,n) in rng f by A2,FINSEQ_6:96; A4: len Upper_Seq(C,n) = (E-max L~Cage(C,n))..f by Th12; now let i1,j1 be set; assume that A5: i1 in dom Upper_Seq(C,n) and A6: j1 in dom Upper_Seq(C,n) and A7: Upper_Seq(C,n).i1 = Upper_Seq(C,n).j1 and A8: i1 <> j1; A9: L~Cage(C,n) = L~f by REVROT_1:33; reconsider i2 = i1, j2 = j1 as Nat by A5,A6; A10: i2 in Seg((E-max L~Cage(C,n))..f) & j2 in Seg((E-max L~Cage(C,n))..f) by A4,A5,A6,FINSEQ_1:def 3; A11: Upper_Seq(C,n).i1 = Upper_Seq(C,n)/.i2 by A5,FINSEQ_4:def 4 .= f/.i2 by A1,A3,A10,FINSEQ_5:46; A12: Upper_Seq(C,n).j1 = Upper_Seq(C,n)/.j2 by A6,FINSEQ_4:def 4 .= f/.j2 by A1,A3,A10,FINSEQ_5:46; A13: 1 <= i2 & 1 <= j2 by A10,FINSEQ_1:3; A14: j2 <= (E-max L~Cage(C,n))..f & i2 <= (E-max L~Cage(C,n))..f by A10,FINSEQ_1:3; (E-max L~f)..f < len f by SPRECT_5:17; then A15: j2 < len f & i2 < len f by A9,A14,AXIOMS:22; per cases by A8,AXIOMS:21; suppose i2 < j2; hence contradiction by A7,A11,A12,A13,A15,GOBOARD7:38; suppose j2 < i2; hence contradiction by A7,A11,A12,A13,A15,GOBOARD7:38; end; hence Upper_Seq(C,n) is one-to-one by FUNCT_1:def 8; thus Upper_Seq(C,n) is special by A1; thus Upper_Seq(C,n) is unfolded by A1; let i,j be Nat; assume A16: i+1 < j; len f <> 0 by FINSEQ_1:25; then len f > 0 by NAT_1:19; then 0+1 <= len f by NAT_1:38; then A17: len f in dom f by FINSEQ_3:27; now per cases; suppose A18: j+1 <= len Upper_Seq(C,n); then A19: LSeg(Upper_Seq(C,n),j) = LSeg(f,j) by A1,SPPOL_2:9; j < len Upper_Seq(C,n) by A18,NAT_1:38; then i+1 <= len Upper_Seq(C,n) by A16,AXIOMS:22; then A20: LSeg(Upper_Seq(C,n),i) = LSeg(f,i) by A1,SPPOL_2:9; A21: j+1 <= (E-max L~Cage(C,n))..f by A1,A3,A18,FINSEQ_5:45; A22: (E-max L~Cage(C,n))..f <= len f by A3,FINSEQ_4:31; now per cases by A21,REAL_1:def 5; suppose j+1 < (E-max L~Cage(C,n))..f; hence j+1 < len f by A22,AXIOMS:22; suppose A23: j+1 = (E-max L~Cage(C,n))..f; assume j+1 >= len f; then (E-max L~Cage(C,n))..f = len f by A22,A23,AXIOMS:21; then E-max L~Cage(C,n) = f.(len f) by A3,FINSEQ_4:29 .= f/.(len f) by A17,FINSEQ_4:def 4 .= f/.1 by FINSEQ_6:def 1 .= W-min L~Cage(C,n) by A2,FINSEQ_6:98; hence contradiction by TOPREAL5:25; end; hence LSeg(Upper_Seq(C,n),i) misses LSeg(Upper_Seq(C,n),j) by A16,A19,A20,GOBOARD5:def 4; suppose j+1 > len Upper_Seq(C,n); then LSeg(Upper_Seq(C,n),j) = {} by TOPREAL1:def 5; then LSeg(Upper_Seq(C,n),i) /\ LSeg(Upper_Seq(C,n),j) = {}; hence LSeg(Upper_Seq(C,n),i) misses LSeg(Upper_Seq(C,n),j) by XBOOLE_0:def 7; end; hence thesis; end; cluster Lower_Seq(C,n) -> one-to-one special unfolded s.n.c.; coherence proof A24: 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 A25: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A24,FINSEQ_6:96; A26: Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by Def2; set f = Rotate(Cage(C,n),W-min L~Cage(C,n)); A27: 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 A28: E-max L~Cage(C,n) in rng f by A27,FINSEQ_6:96; A29: len Lower_Seq(C,n) = len f-(E-max L~Cage(C,n))..f+1 by Th13; A30: L~Cage(C,n) = L~f by REVROT_1:33; then A31: f/.1 = W-min L~f by A27,FINSEQ_6:98; then A32: (W-max L~Cage(C,n))..f <= (N-min L~Cage(C,n))..f by A30,SPRECT_5:24; A33: (N-min L~Cage(C,n))..f < (N-max L~Cage(C,n))..f by A30,A31,SPRECT_5:25; A34: (N-max L~Cage(C,n))..f <= (E-max L~Cage(C,n))..f by A30,A31,SPRECT_5:26; (W-max L~Cage(C,n))..f > 1 by A30,A31,SPRECT_5:23; then (N-min L~Cage(C,n))..f > 1 by A32,AXIOMS:22; then (N-max L~Cage(C,n))..f > 1 by A33,AXIOMS:22; then A35: (E-max L~Cage(C,n))..f > 1 by A34,AXIOMS:22; now let i1,j1 be set; assume that A36: i1 in dom Lower_Seq(C,n) and A37: j1 in dom Lower_Seq(C,n) and A38: Lower_Seq(C,n).i1 = Lower_Seq(C,n).j1 and A39: i1 <> j1; reconsider i2 = i1, j2 = j1 as Nat by A36,A37; A40: i2 in Seg len Lower_Seq(C,n) & j2 in Seg len Lower_Seq(C,n) by A36,A37,FINSEQ_1:def 3; then i2 >= 1 & j2 >= 1 by FINSEQ_1:3; then A41: i2 = i2-'1+1 & j2 = j2-'1+1 by AMI_5:4; A42: Lower_Seq(C,n).i1 = Lower_Seq(C,n)/.i2 by A36,FINSEQ_4:def 4 .= f/.(i2-'1+(E-max L~Cage(C,n))..f) by A26,A28,A36,A41,FINSEQ_5:55; A43: Lower_Seq(C,n).j1 = Lower_Seq(C,n)/.j2 by A37,FINSEQ_4:def 4 .= f/.(j2-'1+(E-max L~Cage(C,n))..f) by A26,A28,A37,A41,FINSEQ_5:55; 0+1 <= i2 & 0+1 <= j2 by A40,FINSEQ_1:3; then A44: i2-1 >= 0 & j2-1 >= 0 by REAL_1:84; j2 <= len f-(E-max L~Cage(C,n))..f+1 & i2 <= len f-(E-max L~Cage(C,n))..f+1 by A29,A40,FINSEQ_1:3; then j2-1 <= len f-(E-max L~Cage(C,n))..f & i2-1 <= len f-(E-max L~Cage(C,n))..f by REAL_1:86; then j2-1+(E-max L~Cage(C,n))..f <= len f & i2-1+(E-max L~Cage(C,n))..f <= len f by REAL_1:84; then A45: j2-'1+(E-max L~Cage(C,n))..f <= len f & i2-'1+(E-max L~Cage(C,n))..f <= len f by A44,BINARITH:def 3; i2-'1+(E-max L~Cage(C,n))..f >= (E-max L~Cage(C,n))..f & j2-'1+(E-max L~Cage(C,n))..f >= (E-max L~Cage(C,n))..f by NAT_1:29; then A46: 1 < i2-'1+(E-max L~Cage(C,n))..f & 1 < j2-'1+(E-max L~Cage(C,n))..f by A35,AXIOMS:22; per cases by A39,AXIOMS:21; suppose i2 < j2; then i2-1 < j2-1 by REAL_1:54; then i2-1 < j2-'1 by A44,BINARITH:def 3; then i2-'1 < j2-'1 by A44,BINARITH:def 3; then i2-'1+(E-max L~Cage(C,n))..f < j2-'1+(E-max L~Cage(C,n))..f by REAL_1:53; hence contradiction by A38,A42,A43,A45,A46,GOBOARD7:39; suppose j2 < i2; then j2-1 < i2-1 by REAL_1:54; then j2-1 < i2-'1 by A44,BINARITH:def 3; then j2-'1 < i2-'1 by A44,BINARITH:def 3; then j2-'1+(E-max L~Cage(C,n))..f < i2-'1+(E-max L~Cage(C,n))..f by REAL_1:53; hence contradiction by A38,A42,A43,A45,A46,GOBOARD7:39; end; hence Lower_Seq(C,n) is one-to-one by FUNCT_1:def 8; thus Lower_Seq(C,n) is special by A25,A26,SPPOL_2:41; thus Lower_Seq(C,n) is unfolded by A25,A26,SPPOL_2:28; let i,j be Nat; assume A47: i+1 < j; i+1 >= 1 by NAT_1:29; then A48: j > 0+1 by A47,AXIOMS:22; then j = j-'1+1 by AMI_5:4; then A49: LSeg(Lower_Seq(C,n),j) = LSeg(f,j-'1+(E-max L~Cage(C,n))..f) by A25,A26,SPPOL_2:10; now per cases by NAT_1:18; suppose i > 0; then A50: i >= 0+1 by NAT_1:38; then i = i-'1+1 by AMI_5:4; then A51: LSeg(Lower_Seq(C,n),i) = LSeg(f,i-'1+(E-max L~Cage(C,n))..f) by A26,A28,SPPOL_2:10; A52: j-1 > 0 by A48,REAL_1:86; A53: i-1 >= 0 by A50,REAL_1:84; i+1-1 < j-1 by A47,REAL_1:54; then i-1+1 < j-1 by XCMPLX_1:29; then i-1+1 < j-'1 by A52,BINARITH:def 3; then i-'1+1 < j-'1 by A53,BINARITH:def 3; then i-'1+1+(E-max L~Cage(C,n))..f < j-'1+(E-max L~Cage(C,n))..f by REAL_1:53; then A54: i-'1+(E-max L~Cage(C,n))..f+1 < j-'1+(E-max L~Cage(C,n))..f by XCMPLX_1:1; i-'1 >= 0 by NAT_1:18; then A55: i-'1+(E-max L~Cage(C,n))..f > 0+1 by A35,REAL_1:67; now per cases; suppose j-'1+(E-max L~Cage(C,n))..f+1 <= len f; then j-'1+(E-max L~Cage(C,n))..f < len f by NAT_1:38; then LSeg(Lower_Seq(C,n),i) misses LSeg(Lower_Seq(C,n),j) by A49,A51,A54,A55,GOBOARD5:def 4; hence LSeg(Lower_Seq(C,n),i) /\ LSeg(Lower_Seq(C,n),j) = {} by XBOOLE_0:def 7; suppose j-'1+(E-max L~Cage(C,n))..f+1 > len f; then LSeg(Lower_Seq(C,n),j) = {} by A49,TOPREAL1:def 5; hence LSeg(Lower_Seq(C,n),i) /\ LSeg(Lower_Seq(C,n),j) = {}; end; hence LSeg(Lower_Seq(C,n),i) /\ LSeg(Lower_Seq(C,n),j) = {}; suppose i = 0; then LSeg(Lower_Seq(C,n),i) = {} by TOPREAL1:def 5; hence LSeg(Lower_Seq(C,n),i) /\ LSeg(Lower_Seq(C,n),j) = {}; end; hence thesis by XBOOLE_0:def 7; end; end; theorem Th14: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds len Upper_Seq(C,n) + len Lower_Seq(C,n) = len Cage(C,n)+1 proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; thus len Upper_Seq(C,n) + len Lower_Seq(C,n) = (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))+ len Lower_Seq(C,n) by Th12 .= (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))+1) by Th13 .= (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)))+1 by XCMPLX_1:1 .= (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))+1 by XCMPLX_1:29 .= len Rotate(Cage(C,n),W-min L~Cage(C,n))+1 by XCMPLX_1:26 .= len Cage(C,n)+1 by REVROT_1:14; end; theorem Th15: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds Rotate(Cage(C,n),W-min L~Cage(C,n)) = Upper_Seq(C,n) ^' Lower_Seq(C,n) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; A1: len (Upper_Seq(C,n) ^' Lower_Seq(C,n)) +1 = len Upper_Seq(C,n) + len Lower_Seq(C,n) by GRAPH_2:13 .= len Cage(C,n)+1 by Th14 .= len Rotate(Cage(C,n),W-min L~Cage(C,n))+1 by REVROT_1:14; then A2: len (Upper_Seq(C,n) ^' Lower_Seq(C,n)) = len Rotate(Cage(C,n),W-min L~Cage(C,n)) by XCMPLX_1:2; now let i be Nat; assume A3: i in Seg len Rotate(Cage(C,n),W-min L~Cage(C,n)); then A4: 1 <= i & i <= len Rotate(Cage(C,n),W-min L~Cage(C,n)) by FINSEQ_1:3; A5: 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 A6: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A5,FINSEQ_6:96; A7: i in dom Rotate(Cage(C,n),W-min L~Cage(C,n)) by A3,FINSEQ_1:def 3; per cases; suppose A8: i <= len Upper_Seq(C,n); then i <= (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) by Th12; then A9: i in Seg ((E-max L~Cage(C,n))..Rotate(Cage(C,n), W-min L~Cage(C,n))) by A4,FINSEQ_1:3; len (Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n)) = (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n)) by A6,FINSEQ_5:45; then A10: i in dom (Rotate(Cage(C,n),W-min L~Cage(C,n))-: E-max L~Cage(C,n)) by A9,FINSEQ_1:def 3; thus (Upper_Seq(C,n) ^' Lower_Seq(C,n)).i = Upper_Seq(C,n).i by A4,A8,GRAPH_2:14 .= (Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n)).i by Def1 .= (Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n))/.i by A10,FINSEQ_4:def 4 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/.i by A6,A9,FINSEQ_5:46 .= Rotate(Cage(C,n),W-min L~Cage(C,n)).i by A7,FINSEQ_4:def 4; suppose i > len Upper_Seq(C,n); then i >= len Upper_Seq(C,n)+1 by NAT_1:38; then consider j be Nat such that A11: i = len Upper_Seq(C,n)+1+j by NAT_1:28; A12: i = len Upper_Seq(C,n)+(j+1) by A11,XCMPLX_1:1; A13: j+1 >= 1 by NAT_1:29; i < len (Upper_Seq(C,n) ^' Lower_Seq(C,n))+1 by A1,A4,NAT_1:38; then i < len Lower_Seq(C,n) + len Upper_Seq(C,n) by GRAPH_2:13; then i-len Upper_Seq(C,n) < len Lower_Seq(C,n) by REAL_1:84; then A14: j+1 < len Lower_Seq(C,n) by A12,XCMPLX_1:26; A15: i = (E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))+(j+1) by A12,Th12; A16: j+1+1 >= 1 by NAT_1:29; A17: len (Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max 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))+1 by A6,FINSEQ_5:53; j+1+(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 A4,A12,Th12; then j+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 REAL_1:84; then j+1+1 <= len (Rotate(Cage(C,n),W-min L~Cage(C,n)):- (E-max L~Cage(C,n))) by A17,REAL_1:55; then j+1+1 in Seg len (Rotate(Cage(C,n),W-min L~Cage(C,n)):- (E-max L~Cage(C,n))) by A16,FINSEQ_1:3; then A18: j+1+1 in dom (Rotate(Cage(C,n),W-min L~Cage(C,n)):- (E-max L~Cage(C,n))) by FINSEQ_1:def 3; thus (Upper_Seq(C,n) ^' Lower_Seq(C,n)).i = Lower_Seq(C,n).(j+1+1) by A12,A13,A14,GRAPH_2:15 .= (Rotate(Cage(C,n),W-min L~Cage(C,n)):-(E-max L~Cage(C,n))). (j+1+1) by Def2 .= (Rotate(Cage(C,n),W-min L~Cage(C,n)):-(E-max L~Cage(C,n)))/. (j+1+1) by A18,FINSEQ_4:def 4 .= Rotate(Cage(C,n),W-min L~Cage(C,n))/. (j+1+(E-max L~Cage(C,n))..Rotate(Cage(C,n),W-min L~Cage(C,n))) by A6,A18,FINSEQ_5:55 .= Rotate(Cage(C,n),W-min L~Cage(C,n)).i by A7,A15,FINSEQ_4:def 4; end; hence Rotate(Cage(C,n),W-min L~Cage(C,n)) = Upper_Seq(C,n) ^' Lower_Seq(C,n) by A2,FINSEQ_2:10; end; theorem for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds L~Cage(C,n) = L~(Upper_Seq(C,n) ^' Lower_Seq(C,n)) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; Rotate(Cage(C,n),W-min L~Cage(C,n)) = Upper_Seq(C,n) ^' Lower_Seq(C,n) by Th15; hence L~Cage(C,n) = L~(Upper_Seq(C,n) ^' Lower_Seq(C,n)) by REVROT_1:33; end; theorem for C be compact non vertical non horizontal non empty Subset of TOP-REAL 2 for n be Nat holds L~Cage(C,n) = L~Upper_Seq(C,n) \/ L~Lower_Seq(C,n) proof let C be compact non vertical non horizontal non empty 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 Def1; A2: Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by Def2; A3: 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 A3,FINSEQ_6:96; then L~Rotate(Cage(C,n),W-min L~Cage(C,n)) = L~Upper_Seq(C,n) \/ L~Lower_Seq(C,n) by A1,A2,SPPOL_2:25; hence thesis by REVROT_1:33; end; theorem Th18: for P be Simple_closed_curve holds W-min(P) <> E-min(P) proof let P be Simple_closed_curve; now assume A1: W-min(P) = E-min(P); A2:|[W-bound P, inf (proj2||W-most P)]|=W-min(P) by PSCOMP_1:def 42; |[E-bound P, inf (proj2||E-most P)]|=E-min(P) by PSCOMP_1:def 47; then W-bound P= E-bound P by A1,A2,SPPOL_2:1; hence contradiction by TOPREAL5:23; end; hence W-min(P) <> E-min(P); end; theorem Th19: for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds len Upper_Seq(C,n) >= 3 & len Lower_Seq(C,n) >= 3 proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; set pWi = W-min L~Cage(C,n); set pWa = W-max L~Cage(C,n); set pEi = E-min L~Cage(C,n); set pEa = E-max L~Cage(C,n); A1: pWi <> pWa by SPRECT_2:62; A2: pWa <> pEa by JORDAN1B:6; pWi <> pEa by TOPREAL5:25; then A3: Card {pWi,pWa,pEa} = 3 by A1,A2,CARD_2:77; A4: Upper_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n) by Def1; A5: Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by Def2; A6: 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 A7: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A6,FINSEQ_6:96; (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)); then A8: pEa in rng Upper_Seq(C,n) by A4,A7,FINSEQ_5:49; A9: Upper_Seq(C,n)/.1 = Rotate(Cage(C,n),W-min L~Cage(C,n))/.1 by A4,A7,FINSEQ_5:47; then A10: Upper_Seq(C,n)/.1 = W-min L~Cage(C,n) by A6,FINSEQ_6:98; then A11: pWi in rng Upper_Seq(C,n) by FINSEQ_6:46; pWa in rng Cage(C,n) by SPRECT_2:48; then A12: pWa in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A6,FINSEQ_6:96; set f=Rotate(Cage(C,n),W-min L~Cage(C,n)); A13: L~Cage(C,n) = L~f by REVROT_1:33; then A14: (W-max L~f)..f <= (N-min L~f)..f by A9,A10,SPRECT_5:24; (N-min L~f)..f < (N-max L~f)..f by A9,A10,A13,SPRECT_5:25; then A15: (W-max L~f)..f < (N-max L~f)..f by A14,AXIOMS:22; (N-max L~f)..f <= (E-max L~f)..f by A9,A10,A13,SPRECT_5:26; then pWa..Rotate(Cage(C,n),W-min L~Cage(C,n)) < pEa..Rotate(Cage(C,n),W-min L~Cage(C,n)) by A13,A15,AXIOMS:22; then A16: pWa in rng Upper_Seq(C,n) by A4,A7,A12,FINSEQ_5:49; {pWi,pWa,pEa} c= rng Upper_Seq(C,n) proof let x be set; assume x in {pWi,pWa,pEa}; hence x in rng Upper_Seq(C,n) by A8,A11,A16,ENUMSET1:def 1; end; then A17: Card {pWi,pWa,pEa} c= Card rng Upper_Seq(C,n) by CARD_1:27; Card rng Upper_Seq(C,n) c= Card dom Upper_Seq(C,n) by YELLOW_6:3; then Card rng Upper_Seq(C,n) c= len Upper_Seq(C,n) by PRE_CIRC:21; then 3 c= len Upper_Seq(C,n) by A3,A17,XBOOLE_1:1; hence len Upper_Seq(C,n) >= 3 by CARD_1:56; A18: pWi <> pEi by Th18; A19: pEi <> pEa by SPRECT_2:58; pWi <> pEa by TOPREAL5:25; then A20: Card {pWi,pEi,pEa} = 3 by A18,A19,CARD_2:77; A21: pEa in rng Lower_Seq(C,n) by A5,FINSEQ_6:66; 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 A5,A7,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 A6,FINSEQ_6:98; then A22: pWi in rng Lower_Seq(C,n) by REVROT_1:3; pEi in rng Cage(C,n) by SPRECT_2:49; then A23: pEi in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A6,FINSEQ_6:96; pEi..Rotate(Cage(C,n),W-min L~Cage(C,n)) > pEa..Rotate(Cage(C,n),W-min L~Cage(C,n)) by A9,A10,A13,SPRECT_5:27; then A24: pEi in rng Lower_Seq(C,n) by A5,A7,A23,FINSEQ_6:67; {pWi,pEi,pEa} c= rng Lower_Seq(C,n) proof let x be set; assume x in {pWi,pEi,pEa}; hence x in rng Lower_Seq(C,n) by A21,A22,A24,ENUMSET1:def 1; end; then A25: Card {pWi,pEi,pEa} c= Card rng Lower_Seq(C,n) by CARD_1:27; Card rng Lower_Seq(C,n) c= Card dom Lower_Seq(C,n) by YELLOW_6:3; then Card rng Lower_Seq(C,n) c= len Lower_Seq(C,n) by PRE_CIRC:21; then 3 c= len Lower_Seq(C,n) by A20,A25,XBOOLE_1:1; hence len Lower_Seq(C,n) >= 3 by CARD_1:56; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; let n be Nat; cluster Upper_Seq(C,n) -> being_S-Seq; coherence proof len Upper_Seq(C,n) >= 3 by Th19; then len Upper_Seq(C,n) >= 2 by AXIOMS:22; hence thesis by TOPREAL1:def 10; end; cluster Lower_Seq(C,n) -> being_S-Seq; coherence proof len Lower_Seq(C,n) >= 3 by Th19; then len Lower_Seq(C,n) >= 2 by AXIOMS:22; hence thesis by TOPREAL1:def 10; end; end; theorem for C be compact non vertical non horizontal Subset of TOP-REAL 2 for n be Nat holds L~Upper_Seq(C,n) /\ L~Lower_Seq(C,n) = {W-min L~Cage(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 Def1; A2: Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by Def2; A3: 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 A4: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A3,FINSEQ_6:96; A5: (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 Lower_Seq(C,n) >= 3 by Th19; then len Lower_Seq(C,n) >= 2 by AXIOMS:22; then A6: rng Lower_Seq(C,n) c= L~Lower_Seq(C,n) by SPPOL_2:18; A7: E-max L~Cage(C,n) in rng Lower_Seq(C,n) by A2,FINSEQ_6:66; A8: len Upper_Seq(C,n) >= 3 by Th19; then len Upper_Seq(C,n) >= 2 by AXIOMS:22; then A9: rng Upper_Seq(C,n) c= L~Upper_Seq(C,n) by SPPOL_2:18; A10: E-max L~Cage(C,n) in rng Upper_Seq(C,n) by A1,A4,A5,FINSEQ_5:49; Upper_Seq(C,n)/.1 = Rotate(Cage(C,n),W-min L~Cage(C,n))/.1 by A1,A4,FINSEQ_5:47 .= W-min L~Cage(C,n) by A3,FINSEQ_6:98; then A11: W-min L~Cage(C,n) in rng Upper_Seq(C,n) by FINSEQ_6:46; 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 A2,A4,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 A3,FINSEQ_6:98; then A12: W-min L~Cage(C,n) in rng Lower_Seq(C,n) by REVROT_1:3; thus L~Upper_Seq(C,n) /\ L~Lower_Seq(C,n) c= {W-min L~Cage(C,n),E-max L~Cage(C,n)} proof let x be set; assume A13: x in L~Upper_Seq(C,n) /\ L~Lower_Seq(C,n); then A14: x in L~Upper_Seq(C,n) & x in L~Lower_Seq(C,n) by XBOOLE_0:def 3; reconsider x1=x as Point of TOP-REAL 2 by A13; consider i1 be Nat such that A15: 1 <= i1 & i1+1 <= len Upper_Seq(C,n) and A16: x1 in LSeg(Upper_Seq(C,n),i1) by A14,SPPOL_2:13; consider i2 be Nat such that A17: 1 <= i2 & i2+1 <= len Lower_Seq(C,n) and A18: x1 in LSeg(Lower_Seq(C,n),i2) by A14,SPPOL_2:13; set f=Rotate(Cage(C,n),W-min L~Cage(C,n)); set pE=E-max L~Cage(C,n); set pW=W-min L~Cage(C,n); A19: LSeg(Upper_Seq(C,n),i1) = LSeg(f,i1) by A1,A15,SPPOL_2:9; set i3=i2-'1; A20: i3+1 = i2 by A17,AMI_5:4; then A21: LSeg(Lower_Seq(C,n),i2) = LSeg(f,i3+pE..f) by A2,A4,SPPOL_2:10; A22: len Upper_Seq(C,n) = pE..f by Th12; A23: len Lower_Seq(C,n) = len f-pE..f+1 by Th13; A24: i2-1 >= 1-1 by A17,REAL_1:49; i2 < len f-pE..f+1 by A17,A23,NAT_1:38; then i2-1 < len f-pE..f by REAL_1:84; then i2-1+pE..f < len f by REAL_1:86; then A25: i3+pE..f < len f by A24,BINARITH:def 3; A26: i3 >= 0 by NAT_1:18; A27: pE..f >= 1 by A4,FINSEQ_4:31; i3+1 < len f-pE..f+1 by A17,A20,A23,NAT_1:38; then i3 < len f-pE..f by REAL_1:55; then A28: i3+pE..f < len f by REAL_1:86; A29: i1+1 < pE..f+1 by A15,A22,NAT_1:38; 1+pE..f <= i3+1+pE..f by A17,A20,REAL_1:55; then i1+1 < i3+1+pE..f by A29,AXIOMS:22; then i1+1 < i3+pE..f+1 by XCMPLX_1:1; then A30: i1+1 <= i3+pE..f by NAT_1:38; A31: i3+pE..f+1 <= len f by A28,NAT_1:38; A32: len f > 4 by GOBOARD7:36; A33: i3+pE..f >= 0 & i1 >= 0 by NAT_1:18; A34: pE..f-'1+1 = pE..f by A27,AMI_5:4; assume A35: not x in {W-min L~Cage(C,n),E-max L~Cage(C,n)}; now per cases by A15,A30,REAL_1:def 5; suppose i1+1 < i3+pE..f & i1 > 1; then LSeg(f,i1) misses LSeg(f,i3+pE..f) by A28,GOBOARD5:def 4; then LSeg(f,i1) /\ LSeg(f,i3+pE..f) = {} by XBOOLE_0:def 7; hence contradiction by A16,A18,A19,A21,XBOOLE_0:def 3; suppose A36: i1 = 1; i3+pE..f >= 0+3 by A8,A22,A26,REAL_1:55; then A37: i1+1 < i3+pE..f by A36,AXIOMS:22; now per cases by A31,REAL_1:def 5; suppose i3+pE..f+1 < len f; then LSeg(f,i1) misses LSeg(f,i3+pE..f) by A37,GOBOARD5:def 4; then LSeg(f,i1) /\ LSeg(f,i3+pE..f) = {} by XBOOLE_0:def 7; hence contradiction by A16,A18,A19,A21,XBOOLE_0:def 3; suppose i3+pE..f+1 = len f; then i3+pE..f = len f-1 by XCMPLX_1:26; then i3+pE..f = len f-'1 by A33,BINARITH:def 3; then LSeg(f,i1) /\ LSeg(f,i3+pE..f) = {f/.1} by A32,A36,REVROT_1:30; then x1 in {f/.1} by A16,A18,A19,A21,XBOOLE_0:def 3; then x1 = f/.1 by TARSKI:def 1 .= pW by A3,FINSEQ_6:98; hence contradiction by A35,TARSKI:def 2; end; hence contradiction; suppose A38: i1+1 = i3+pE..f; 0+pE..f <= i3+pE..f by A26,REAL_1:55; then pE..f = i1+1 by A15,A22,A38,AXIOMS:21; then i1 = pE..f-1 by XCMPLX_1:26; then A39: i1 = pE..f-'1 by A33,BINARITH:def 3; i3+pE..f >= pE..f by NAT_1:29; then pE..f < len f by A25,AXIOMS:22; then pE..f+1 <= len f by NAT_1:38; then pE..f-'1 + (1+1) <= len f by A34,XCMPLX_1:1; then LSeg(f,i1) /\ LSeg(f,i3+(pE..f)) = {f/.(pE..f)} by A15,A34,A38,A39,TOPREAL1:def 8; then x1 in {f/.(pE..f)} by A16,A18,A19,A21,XBOOLE_0:def 3; then x1 = f/.(pE..f) by TARSKI:def 1 .= pE by A4,FINSEQ_5:41; hence contradiction by A35,TARSKI:def 2; end; hence contradiction; end; thus {W-min L~Cage(C,n),E-max L~Cage(C,n)} c= L~Upper_Seq(C,n) /\ L~Lower_Seq(C,n) proof let x be set; assume A40: x in {W-min L~Cage(C,n),E-max L~Cage(C,n)}; per cases by A40,TARSKI:def 2; suppose x = W-min L~Cage(C,n); hence x in L~Upper_Seq(C,n) /\ L~Lower_Seq(C,n) by A6,A9,A11,A12,XBOOLE_0:def 3; suppose x = E-max L~Cage(C,n); hence x in L~Upper_Seq(C,n) /\ L~Lower_Seq(C,n) by A6,A7,A9,A10,XBOOLE_0:def 3; end; end; theorem for C be compact non vertical non horizontal Subset of TOP-REAL 2 holds Upper_Seq(C,n) is_in_the_area_of Cage(C,n) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; A1: Upper_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n))-:E-max L~Cage(C,n) by Def1; 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 A3: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A2,FINSEQ_6:96; Rotate(Cage(C,n),W-min L~Cage(C,n)) is_in_the_area_of Cage(C,n) by JORDAN1B:11; hence Upper_Seq(C,n) is_in_the_area_of Cage(C,n) by A1,A3,Th5; end; theorem for C be compact non vertical non horizontal Subset of TOP-REAL 2 holds Lower_Seq(C,n) is_in_the_area_of Cage(C,n) proof let C be compact non vertical non horizontal Subset of TOP-REAL 2; A1: Lower_Seq(C,n) = Rotate(Cage(C,n),W-min L~Cage(C,n)):-E-max L~Cage(C,n) by Def2; 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 A3: E-max L~Cage(C,n) in rng Rotate(Cage(C,n),W-min L~Cage(C,n)) by A2,FINSEQ_6:96; Rotate(Cage(C,n),W-min L~Cage(C,n)) is_in_the_area_of Cage(C,n) by JORDAN1B:11; hence thesis by A1,A3,Th6; end; theorem for C be compact connected non vertical non horizontal Subset of TOP-REAL 2 holds (Cage(C,n)/.2)`2 = N-bound L~Cage(C,n) proof let C be compact connected non vertical non horizontal Subset of TOP-REAL 2; Cage(C,n)/.1 = N-min L~Cage(C,n) by JORDAN9:34; then Cage(C,n)/.2 in N-most L~Cage(C,n) by SPRECT_2:34; then (Cage(C,n)/.2)`2 = (N-min L~Cage(C,n))`2 by PSCOMP_1:98; hence thesis by PSCOMP_1:94; end; theorem for C be compact connected non vertical non horizontal Subset of TOP-REAL 2 for k be Nat st 1 <= k & k+1 <= len Cage(C,n) & Cage(C,n)/.k = E-max L~Cage(C,n) holds (Cage(C,n)/.(k+1))`1 = E-bound L~Cage(C,n) proof let C be compact connected non vertical non horizontal Subset of TOP-REAL 2; A1: Cage(C,n) is_sequence_on Gauge(C,n) by JORDAN9:def 1; let k be Nat; assume that A2: 1 <= k and A3: k+1 <= len Cage(C,n) and A4: Cage(C,n)/.k = E-max L~Cage(C,n); A5: Cage(C,n)/.1 = N-min L~Cage(C,n) by JORDAN9:34; then A6: 1 < (N-max L~Cage(C,n))..Cage(C,n) by SPRECT_2:73; (N-max L~Cage(C,n))..Cage(C,n) <= (E-max L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:74; then A7: (E-max L~Cage(C,n))..Cage(C,n) > 1 by A6,AXIOMS:22; A8: k < len Cage(C,n) by A3,NAT_1:38; then A9: k in dom Cage(C,n) by A2,FINSEQ_3:27; then (E-max L~Cage(C,n))..Cage(C,n) <= k by A4,FINSEQ_5:42; then A10: k > 1 by A7,AXIOMS:22; then consider i1,j1,i2,j2 be Nat such that A11: [i1,j1] in Indices Gauge(C,n) and A12: Cage(C,n)/.k = Gauge(C,n)*(i1,j1) and A13: [i2,j2] in Indices Gauge(C,n) and A14: Cage(C,n)/.(k+1) = Gauge(C,n)*(i2,j2) and A15: 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,A3,JORDAN8:6; A16: 1 <= i1 & i1 <= len Gauge(C,n) & 1 <= j1 & j1 <= width Gauge(C,n) by A11,GOBOARD5:1; A17: 1 <= i2 & i2 <= len Gauge(C,n) & 1 <= j2 & j2 <= width Gauge(C,n) by A13,GOBOARD5:1; A18: len Gauge(C,n) = width Gauge(C,n) by JORDAN8:def 1; Gauge(C,n)*(i1,j1)`1 = E-bound L~Cage(C,n) by A4,A12,PSCOMP_1:104 .= Gauge(C,n)*(len Gauge(C,n),j1)`1 by A16,A18,JORDAN1A:92; then A19: i1 <= len Gauge(C,n) & i1 >= len Gauge(C,n) by A16,GOBOARD5:4; then A20: i1 = len Gauge(C,n) by AXIOMS:21; reconsider k'=k-1 as Nat by A9,FINSEQ_3:28; k >= 1+1 by A10,NAT_1:38; then A21: k' >= 1+1-1 by REAL_1:49; A22: k'+1 < len Cage(C,n) by A8,XCMPLX_1:27; then consider i3,j3,i4,j4 be Nat such that A23: [i3,j3] in Indices Gauge(C,n) and A24: Cage(C,n)/.k' = Gauge(C,n)*(i3,j3) and A25: [i4,j4] in Indices Gauge(C,n) and A26: Cage(C,n)/.(k'+1) = Gauge(C,n)*(i4,j4) and A27: i3 = i4 & j3+1 = j4 or i3+1 = i4 & j3 = j4 or i3 = i4+1 & j3 = j4 or i3 = i4 & j3 = j4+1 by A1,A21,JORDAN8:6; A28: k'+1 = k by XCMPLX_1:27; then A29: i1 = i4 & j1 = j4 by A11,A12,A25,A26,GOBOARD1:21; A30: 1 <= i3 & i3 <= len Gauge(C,n) & 1 <= j3 & j3 <= width Gauge(C,n) by A23,GOBOARD5:1; A31: j3 = j4 proof assume A32: j3 <> j4; per cases by A27,A32; suppose i3 = i4 & j3+1 = j4; hence contradiction by A19,A21,A22,A23,A24,A25,A26,A29,JORDAN10:1; suppose A33: i3 = i4 & j3 = j4+1; k' < len Cage(C,n) by A22,NAT_1:38; then Gauge(C,n)*(i3,j3) in E-most L~Cage(C,n) by A20,A21,A24,A29,A30,A33,JORDAN1A:82; then A34: (Gauge(C,n)*(i4,j4+1))`2 <= (Gauge(C,n)*(i4,j4))`2 by A4,A26,A28,A33,PSCOMP_1:108; j4 < j4+1 by NAT_1:38; hence contradiction by A16,A29,A30,A33,A34,GOBOARD5:5; end; i1 = i2 proof assume A35: i1 <> i2; per cases by A15,A35; suppose i1+1 = i2 & j1 = j2; hence contradiction by A17,A19,NAT_1:38; suppose i1 = i2+1 & j1 = j2; then A36: Cage(C,n)/.(k+1) = Cage(C,n)/.k' by A14,A19,A24,A27,A29,A30,A31,NAT_1:38,XCMPLX_1:2 ; k'+1+1 <= len Cage(C,n) by A22,NAT_1:38; then k'+(1+1) <= len Cage(C,n) by XCMPLX_1:1; then A37: LSeg(Cage(C,n),k') /\ LSeg(Cage(C,n),k) = {Cage(C,n)/.k} by A21,A28,TOPREAL1:def 8; Cage(C,n)/.k' in LSeg(Cage(C,n),k') & Cage(C,n)/.(k+1) in LSeg(Cage(C,n),k) by A2,A3,A8,A21,A28,TOPREAL1:27; then Cage(C,n)/.(k+1) in {Cage(C,n)/.k} by A36,A37,XBOOLE_0:def 3; then Cage(C,n)/.(k+1) = Cage(C,n)/.k by TARSKI:def 1; hence contradiction by A11,A12,A13,A14,A35,GOBOARD1:21; end; then Gauge(C,n)*(i1,j1)`1 = Gauge(C,n)*(i2,1)`1 by A16,GOBOARD5:3 .= Gauge(C,n)*(i2,j2)`1 by A17,GOBOARD5:3; hence thesis by A4,A12,A14,PSCOMP_1:104; end; theorem for C be compact connected non vertical non horizontal Subset of TOP-REAL 2 for k be Nat st 1 <= k & k+1 <= len Cage(C,n) & Cage(C,n)/.k = S-max L~Cage(C,n) holds (Cage(C,n)/.(k+1))`2 = S-bound L~Cage(C,n) proof let C be compact connected non vertical non horizontal Subset of TOP-REAL 2; A1: Cage(C,n) is_sequence_on Gauge(C,n) by JORDAN9:def 1; let k be Nat; assume that A2: 1 <= k and A3: k+1 <= len Cage(C,n) and A4: Cage(C,n)/.k = S-max L~Cage(C,n); A5: Cage(C,n)/.1 = N-min L~Cage(C,n) by JORDAN9:34; then A6: 1 < (N-max L~Cage(C,n))..Cage(C,n) by SPRECT_2:73; (N-max L~Cage(C,n))..Cage(C,n) <= (E-max L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:74; then A7: 1 < (E-max L~Cage(C,n))..Cage(C,n) by A6,AXIOMS:22; (E-max L~Cage(C,n))..Cage(C,n) < (E-min L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:75; then A8: 1 < (E-min L~Cage(C,n))..Cage(C,n) by A7,AXIOMS:22; (E-min L~Cage(C,n))..Cage(C,n) <= (S-max L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:76; then A9: (S-max L~Cage(C,n))..Cage(C,n) > 1 by A8,AXIOMS:22; A10: k < len Cage(C,n) by A3,NAT_1:38; then A11: k in dom Cage(C,n) by A2,FINSEQ_3:27; then (S-max L~Cage(C,n))..Cage(C,n) <= k by A4,FINSEQ_5:42; then A12: k > 1 by A9,AXIOMS:22; then consider i1,j1,i2,j2 be Nat such that A13: [i1,j1] in Indices Gauge(C,n) and A14: Cage(C,n)/.k = Gauge(C,n)*(i1,j1) and A15: [i2,j2] in Indices Gauge(C,n) and A16: Cage(C,n)/.(k+1) = Gauge(C,n)*(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 A1,A3,JORDAN8:6; A18: 1 <= i1 & i1 <= len Gauge(C,n) & 1 <= j1 & j1 <= width Gauge(C,n) by A13,GOBOARD5:1; A19: 1 <= i2 & i2 <= len Gauge(C,n) & 1 <= j2 & j2 <= width Gauge(C,n) by A15,GOBOARD5:1; Gauge(C,n)*(i1,j1)`2 = S-bound L~Cage(C,n) by A4,A14,PSCOMP_1:114 .= Gauge(C,n)*(i1,1)`2 by A18,JORDAN1A:93; then A20: j1 <= 1 & j1 >= 1 by A18,GOBOARD5:5; then A21: j1 = 1 by AXIOMS:21; reconsider k'=k-1 as Nat by A11,FINSEQ_3:28; k >= 1+1 by A12,NAT_1:38; then A22: k' >= 1+1-1 by REAL_1:49; A23: k'+1 < len Cage(C,n) by A10,XCMPLX_1:27; then consider i3,j3,i4,j4 be Nat such that A24: [i3,j3] in Indices Gauge(C,n) and A25: Cage(C,n)/.k' = Gauge(C,n)*(i3,j3) and A26: [i4,j4] in Indices Gauge(C,n) and A27: Cage(C,n)/.(k'+1) = Gauge(C,n)*(i4,j4) and A28: i3 = i4 & j3+1 = j4 or i3+1 = i4 & j3 = j4 or i3 = i4+1 & j3 = j4 or i3 = i4 & j3 = j4+1 by A1,A22,JORDAN8:6; A29: k'+1 = k by XCMPLX_1:27; then A30: i1 = i4 & j1 = j4 by A13,A14,A26,A27,GOBOARD1:21; A31: 1 <= i3 & i3 <= len Gauge(C,n) & 1 <= j3 & j3 <= width Gauge(C,n) by A24,GOBOARD5:1; A32: i3 = i4 proof assume A33: i3 <> i4; per cases by A28,A33; suppose j3 = j4 & i3+1 = i4; hence contradiction by A20,A22,A23,A24,A25,A26,A27,A30,JORDAN10:3; suppose A34: j3 = j4 & i3 = i4+1; k' < len Cage(C,n) by A23,NAT_1:38; then Gauge(C,n)*(i3,j3) in S-most L~Cage(C,n) by A21,A22,A25,A30,A31,A34,JORDAN1A:81; then A35: (Gauge(C,n)*(i4+1,j4))`1 <= (Gauge(C,n)*(i4,j4))`1 by A4,A27,A29,A34,PSCOMP_1:118; i4 < i4+1 by NAT_1:38; hence contradiction by A18,A30,A31,A34,A35,GOBOARD5:4; end; j1 = j2 proof assume A36: j1 <> j2; per cases by A17,A36; suppose j1 = j2+1 & i1 = i2; hence contradiction by A19,A20,NAT_1:38; suppose A37: j1+1 = j2 & i1 = i2; k'+1+1 <= len Cage(C,n) by A23,NAT_1:38; then k'+(1+1) <= len Cage(C,n) by XCMPLX_1:1; then A38: LSeg(Cage(C,n),k') /\ LSeg(Cage(C,n),k) = {Cage(C,n)/.k} by A22,A29,TOPREAL1:def 8; Cage(C,n)/.k' in LSeg(Cage(C,n),k') & Cage(C,n)/.(k+1) in LSeg(Cage(C,n),k) by A2,A3,A10,A22,A29,TOPREAL1:27; then Cage(C,n)/.(k+1) in {Cage(C,n)/.k} by A16,A20,A25,A28,A30,A31,A32,A37,A38,NAT_1:38,XBOOLE_0:def 3; then Cage(C,n)/.(k+1) = Cage(C,n)/.k by TARSKI:def 1; hence contradiction by A13,A14,A15,A16,A36,GOBOARD1:21; end; then Gauge(C,n)*(i1,j1)`2 = Gauge(C,n)*(1,j2)`2 by A18,GOBOARD5:2 .= Gauge(C,n)*(i2,j2)`2 by A19,GOBOARD5:2; hence thesis by A4,A14,A16,PSCOMP_1:114; end; theorem for C be compact connected non vertical non horizontal Subset of TOP-REAL 2 for k be Nat st 1 <= k & k+1 <= len Cage(C,n) & Cage(C,n)/.k = W-min L~Cage(C,n) holds (Cage(C,n)/.(k+1))`1 = W-bound L~Cage(C,n) proof let C be compact connected non vertical non horizontal Subset of TOP-REAL 2; A1: Cage(C,n) is_sequence_on Gauge(C,n) by JORDAN9:def 1; let k be Nat; assume that A2: 1 <= k and A3: k+1 <= len Cage(C,n) and A4: Cage(C,n)/.k = W-min L~Cage(C,n); A5: Cage(C,n)/.1 = N-min L~Cage(C,n) by JORDAN9:34; then A6: 1 < (N-max L~Cage(C,n))..Cage(C,n) by SPRECT_2:73; (N-max L~Cage(C,n))..Cage(C,n) <= (E-max L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:74; then A7: 1 < (E-max L~Cage(C,n))..Cage(C,n) by A6,AXIOMS:22; (E-max L~Cage(C,n))..Cage(C,n) < (E-min L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:75; then A8: 1 < (E-min L~Cage(C,n))..Cage(C,n) by A7,AXIOMS:22; (E-min L~Cage(C,n))..Cage(C,n) <= (S-max L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:76; then A9: 1 < (S-max L~Cage(C,n))..Cage(C,n) by A8,AXIOMS:22; (S-max L~Cage(C,n))..Cage(C,n) < (S-min L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:77; then A10: 1 < (S-min L~Cage(C,n))..Cage(C,n) by A9,AXIOMS:22; (S-min L~Cage(C,n))..Cage(C,n) <= (W-min L~Cage(C,n))..Cage(C,n) by A5,SPRECT_2:78; then A11: (W-min L~Cage(C,n))..Cage(C,n) > 1 by A10,AXIOMS:22; A12: k < len Cage(C,n) by A3,NAT_1:38; then A13: k in dom Cage(C,n) by A2,FINSEQ_3:27; then (W-min L~Cage(C,n))..Cage(C,n) <= k by A4,FINSEQ_5:42; then A14: k > 1 by A11,AXIOMS:22; then consider i1,j1,i2,j2 be Nat such that A15: [i1,j1] in Indices Gauge(C,n) and A16: Cage(C,n)/.k = Gauge(C,n)*(i1,j1) and A17: [i2,j2] in Indices Gauge(C,n) and A18: Cage(C,n)/.(k+1) = Gauge(C,n)*(i2,j2) and A19: 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,A3,JORDAN8:6; A20: 1 <= i1 & i1 <= len Gauge(C,n) & 1 <= j1 & j1 <= width Gauge(C,n) by A15,GOBOARD5:1; A21: 1 <= i2 & i2 <= len Gauge(C,n) & 1 <= j2 & j2 <= width Gauge(C,n) by A17,GOBOARD5:1; A22: len Gauge(C,n) = width Gauge(C,n) by JORDAN8:def 1; Gauge(C,n)*(i1,j1)`1 = W-bound L~Cage(C,n) by A4,A16,PSCOMP_1:84 .= Gauge(C,n)*(1,j1)`1 by A20,A22,JORDAN1A:94; then A23: i1 <= 1 & i1 >= 1 by A20,GOBOARD5:4; then A24: i1 = 1 by AXIOMS:21; reconsider k'=k-1 as Nat by A13,FINSEQ_3:28; k >= 1+1 by A14,NAT_1:38; then A25: k' >= 1+1-1 by REAL_1:49; A26: k'+1 < len Cage(C,n) by A12,XCMPLX_1:27; then consider i3,j3,i4,j4 be Nat such that A27: [i3,j3] in Indices Gauge(C,n) and A28: Cage(C,n)/.k' = Gauge(C,n)*(i3,j3) and A29: [i4,j4] in Indices Gauge(C,n) and A30: Cage(C,n)/.(k'+1) = Gauge(C,n)*(i4,j4) and A31: i3 = i4 & j3+1 = j4 or i3+1 = i4 & j3 = j4 or i3 = i4+1 & j3 = j4 or i3 = i4 & j3 = j4+1 by A1,A25,JORDAN8:6; A32: k'+1 = k by XCMPLX_1:27; then A33: i1 = i4 & j1 = j4 by A15,A16,A29,A30,GOBOARD1:21; A34: 1 <= i3 & i3 <= len Gauge(C,n) & 1 <= j3 & j3 <= width Gauge(C,n) by A27,GOBOARD5:1; A35: j3 = j4 proof assume A36: j3 <> j4; per cases by A31,A36; suppose i3 = i4 & j3 = j4+1; hence contradiction by A23,A25,A26,A27,A28,A29,A30,A33,JORDAN10:2; suppose A37: i3 = i4 & j3+1 = j4; k' < len Cage(C,n) by A26,NAT_1:38; then Gauge(C,n)*(i3,j3) in W-most L~Cage(C,n) by A24,A25,A28,A33,A34,A37,JORDAN1A:80; then A38: (Gauge(C,n)*(i3,j3+1))`2 <= (Gauge(C,n)*(i3,j3))`2 by A4,A30,A32,A37,PSCOMP_1:88; j3 < j3+1 by NAT_1:38; hence contradiction by A20,A33,A34,A37,A38,GOBOARD5:5; end; i1 = i2 proof assume A39: i1 <> i2; per cases by A19,A39; suppose i1 = i2+1 & j1 = j2; hence contradiction by A21,A23,NAT_1:38; suppose A40: i1+1 = i2 & j1 = j2; k'+1+1 <= len Cage(C,n) by A26,NAT_1:38; then k'+(1+1) <= len Cage(C,n) by XCMPLX_1:1; then A41: LSeg(Cage(C,n),k') /\ LSeg(Cage(C,n),k) = {Cage(C,n)/.k} by A25,A32,TOPREAL1:def 8; Cage(C,n)/.k' in LSeg(Cage(C,n),k') & Cage(C,n)/.(k+1) in LSeg(Cage(C,n),k) by A2,A3,A12,A25,A32,TOPREAL1:27; then Cage(C,n)/.(k+1) in {Cage(C,n)/.k} by A18,A23,A28,A31,A33,A34,A35,A40,A41,NAT_1:38,XBOOLE_0:def 3; then Cage(C,n)/.(k+1) = Cage(C,n)/.k by TARSKI:def 1; hence contradiction by A15,A16,A17,A18,A39,GOBOARD1:21; end; then Gauge(C,n)*(i1,j1)`1 = Gauge(C,n)*(i2,1)`1 by A20,GOBOARD5:3 .= Gauge(C,n)*(i2,j2)`1 by A21,GOBOARD5:3; hence thesis by A4,A16,A18,PSCOMP_1:84; end;