Copyright (c) 1999 Association of Mizar Users
environ vocabulary RELAT_2, COMPTS_1, SPPOL_1, EUCLID, TOPREAL1, FINSEQ_1, JORDAN9, MATRIX_1, JORDAN8, GOBOARD1, GOBOARD5, TREES_1, BOOLE, ARYTM_1, TARSKI, PSCOMP_1, ARYTM_3, GROUP_1, MCART_1, PRE_TOPC, GOBOARD9, TOPS_1, SUBSET_1, CONNSP_1, RELAT_1, JORDAN2C, LATTICES, CONNSP_3, SETFAM_1, TOPREAL4, PCOMPS_1, WEIERSTR, METRIC_1, JORDAN10, FINSEQ_4; notation TARSKI, XBOOLE_0, SUBSET_1, SETFAM_1, XREAL_0, REAL_1, NAT_1, BINARITH, STRUCT_0, METRIC_1, TBSP_1, FINSEQ_1, NEWTON, FINSEQ_4, WEIERSTR, PRE_TOPC, TOPS_1, CONNSP_1, CONNSP_3, COMPTS_1, PCOMPS_1, MATRIX_1, EUCLID, TOPREAL1, GOBOARD1, GOBOARD5, TOPREAL4, PSCOMP_1, GOBOARD9, SPPOL_1, JORDAN2C, JORDAN8, GOBRD13, GOBRD14, JORDAN9; constructors BINARITH, CARD_4, CONNSP_1, CONNSP_3, FINSEQ_4, GOBOARD9, GOBRD13, GOBRD14, JORDAN2C, JORDAN8, JORDAN9, PSCOMP_1, REAL_1, REALSET1, TBSP_1, TOPREAL4, TOPS_1, WEIERSTR, JORDAN1; clusters XREAL_0, BORSUK_2, EUCLID, GOBRD14, JORDAN8, PCOMPS_1, PRE_TOPC, PSCOMP_1, RELSET_1, SPPOL_2, SPRECT_1, STRUCT_0, TOPREAL6, SUBSET_1, FINSEQ_1, ARYTM_3, SPRECT_4, JORDAN2C, MEMBERED; requirements REAL, NUMERALS, SUBSET, BOOLE, ARITHM; definitions TARSKI, XBOOLE_0; theorems AXIOMS, BINARITH, CONNSP_1, CONNSP_3, EUCLID, GOBOARD5, GOBOARD6, GOBOARD7, GOBOARD9, GOBRD11, GOBRD13, GOBRD14, HEINE, JGRAPH_1, JORDAN1, JORDAN2C, JORDAN3, JORDAN6, JORDAN8, JORDAN9, NEWTON, NAT_1, PRE_TOPC, PSCOMP_1, REAL_1, REAL_2, RLVECT_1, SETFAM_1, SPPOL_1, SPPOL_2, SPRECT_1, SPRECT_3, SPRECT_4, SUBSET_1, TARSKI, TOPREAL1, TOPREAL3, TOPREAL4, TOPREAL6, TOPS_1, WEIERSTR, ZFMISC_1, XBOOLE_0, XBOOLE_1, SQUARE_1, XCMPLX_0, XCMPLX_1; schemes NAT_1; begin :: Properties of the external approximation of Jordan's curve definition cluster connected compact non vertical non horizontal Subset of TOP-REAL 2; existence proof take R^2-unit_square; thus thesis; end; end; reserve i, j, k, n for Nat, P for Subset of TOP-REAL 2, C for connected compact non vertical non horizontal Subset of TOP-REAL 2; theorem Th1: 1 <= k & k+1 <= len Cage(C,n) & [i,j] in Indices Gauge(C,n) & [i,j+1] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i,j) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i,j+1) implies i < len Gauge(C,n) proof set f = Cage(C,n), G = Gauge(C,n); assume that A1: 1 <= k & k+1 <= len Cage(C,n) and A2: [i,j] in Indices Gauge(C,n) and A3: [i,j+1] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i,j) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i,j+1); A4: i <= len G by A2,GOBOARD5:1; assume i >= len G; then A5: i = len G by A4,REAL_1:def 5; f is_sequence_on G by JORDAN9:def 1; then A6: right_cell(f,k,G) = cell(G,i,j) by A1,A2,A3,GOBRD13:23; len G = width G by JORDAN8:def 1; then j <= len G by A2,GOBOARD5:1; then cell(G,len G,j) misses C by JORDAN8:19; hence contradiction by A1,A5,A6,JORDAN9:33; end; theorem Th2: 1 <= k & k+1 <= len Cage(C,n) & [i,j] in Indices Gauge(C,n) & [i,j+1] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i,j+1) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i,j) implies i > 1 proof set f = Cage(C,n), G = Gauge(C,n); assume that A1: 1 <= k & k+1 <= len Cage(C,n) and A2: [i,j] in Indices Gauge(C,n) and A3: [i,j+1] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i,j+1) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i,j); A4: 1 <= i by A2,GOBOARD5:1; assume i <= 1; then i = 1 by A4,REAL_1:def 5; then A5: i-'1 = 0 by GOBOARD9:1; f is_sequence_on G by JORDAN9:def 1; then A6: right_cell(f,k,G) = cell(G,i-'1,j) by A1,A2,A3,GOBRD13:29; len G = width G by JORDAN8:def 1; then j <= len G by A2,GOBOARD5:1; then cell(G,0,j) misses C by JORDAN8:21; hence contradiction by A1,A5,A6,JORDAN9:33; end; theorem Th3: 1 <= k & k+1 <= len Cage(C,n) & [i,j] in Indices Gauge(C,n) & [i+1,j] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i,j) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i+1,j) implies j > 1 proof set f = Cage(C,n), G = Gauge(C,n); assume that A1: 1 <= k & k+1 <= len Cage(C,n) and A2: [i,j] in Indices Gauge(C,n) and A3: [i+1,j] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i,j) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i+1,j); A4: 1 <= j by A2,GOBOARD5:1; assume j <= 1; then j = 1 by A4,REAL_1:def 5; then A5: j-'1 = 0 by GOBOARD9:1; f is_sequence_on G by JORDAN9:def 1; then A6: right_cell(f,k,G) = cell(G,i,j-'1) by A1,A2,A3,GOBRD13:25; i <= len G by A2,GOBOARD5:1; then cell(G,i,0) misses C by JORDAN8:20; hence contradiction by A1,A5,A6,JORDAN9:33; end; theorem Th4: 1 <= k & k+1 <= len Cage(C,n) & [i,j] in Indices Gauge(C,n) & [i+1,j] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i+1,j) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i,j) implies j < width Gauge(C,n) proof set f = Cage(C,n), G = Gauge(C,n); assume that A1: 1 <= k & k+1 <= len Cage(C,n) and A2: [i,j] in Indices Gauge(C,n) and A3: [i+1,j] in Indices Gauge(C,n) & Cage(C,n)/.k = Gauge(C,n)*(i+1,j) & Cage(C,n)/.(k+1) = Gauge(C,n)*(i,j); A4: j <= width G by A2,GOBOARD5:1; assume j >= width G; then A5: j = width G by A4,REAL_1:def 5; f is_sequence_on G by JORDAN9:def 1; then A6: right_cell(f,k,G) = cell(G,i,j) by A1,A2,A3,GOBRD13:27; A7: len G = width G by JORDAN8:def 1; i <= len G by A2,GOBOARD5:1; then cell(G,i,len G) misses C by JORDAN8:18; hence contradiction by A1,A5,A6,A7,JORDAN9:33; end; theorem Th5: C misses L~Cage(C,n) proof set f = Cage(C,n), G = Gauge(C,n); assume not thesis; then consider c being set such that A1: c in C & c in L~f by XBOOLE_0:3; L~f = union { LSeg(f,i) where i is Nat: 1 <= i & i+1 <= len f } by TOPREAL1:def 6; then consider Z being set such that A2: c in Z and A3: Z in { LSeg(f,i) where i is Nat: 1 <= i & i+1 <= len f } by A1,TARSKI:def 4; consider i being Nat such that A4: Z = LSeg(f,i) and A5: 1 <= i & i+1 <= len f by A3; f is_sequence_on G by JORDAN9:def 1; then LSeg(f,i) = left_cell(f,i,G) /\ right_cell(f,i,G) by A5,GOBRD13:30; then A6: c in left_cell(f,i,G) by A2,A4,XBOOLE_0:def 3; left_cell(f,i,G) misses C by A5,JORDAN9:33; hence contradiction by A1,A6,XBOOLE_0:3; end; theorem Th6: N-bound L~Cage(C,n) = N-bound C + (N-bound C - S-bound C)/(2|^n) proof set a = N-bound C, s = S-bound C, w = W-bound C, f = Cage(C,n), G = Gauge(C,n); consider i such that A1: 1 <= i & i+1 <= len G and A2: f/.1 = G*(i,width G) and f/.2 = G*(i+1,width G) & N-min C in cell(G,i,width G-'1) & N-min C <> G*(i,width G-'1) by JORDAN9:def 1; A3: len G = width G by JORDAN8:def 1; i+0 <= i+1 by AXIOMS:24; then A4: i <= len G by A1,AXIOMS:22; 4 <= len G by JORDAN8:13; then 1 <= len G by AXIOMS:22; then A5: [i,len G] in Indices G by A1,A3,A4,GOBOARD7:10; A6: 2|^n <> 0 by HEINE:5; thus N-bound L~f = (N-min L~f)`2 by PSCOMP_1:94 .= (f/.1)`2 by JORDAN9:34 .= |[w+((E-bound C-w)/(2|^n))*(i-2), s+((a-s)/(2|^n))*(len G-2)]|`2 by A2,A3,A5,JORDAN8:def 1 .= s+((a-s)/(2|^n))*(len G-2) by EUCLID:56 .= s+((a-s)/(2|^n))*(2|^n+3-2) by JORDAN8:def 1 .= s+((a-s)/(2|^n))*(2|^n+(3-2)) by XCMPLX_1:29 .= s+(((a-s)/(2|^n))*2|^n+((a-s)/(2|^n))*1) by XCMPLX_1:8 .= s+((a-s)/(2|^n))*2|^n+(a-s)/(2|^n) by XCMPLX_1:1 .= s+(a-s)+(a-s)/(2|^n) by A6,XCMPLX_1:88 .= a+(a-s)/(2|^n) by XCMPLX_1:27; end; theorem Th7: i < j implies N-bound L~Cage(C,j) < N-bound L~Cage(C,i) proof assume A1: i < j; defpred P[Nat] means i < $1 implies N-bound L~Cage(C,$1) < N-bound L~Cage(C,i); A2: P[0] by NAT_1:18; A3: for n being Nat st P[n] holds P[n+1] proof let n be Nat; assume A4: P[n]; assume i < n+1; then A5: i <= n by NAT_1:38; set j = n + 1, a = N-bound C, s = S-bound C; A6: N-bound L~Cage(C,n) = a+(a-s)/(2|^n) & N-bound L~Cage(C,j) = a+(a-s)/(2|^j) by Th6; 2|^n > 0 by HEINE:5; then A7: 2|^n*2 > 0 * 2 by REAL_1:70; s < a by SPRECT_1:34; then A8: s - a < 0 by REAL_2:105; a+(a-s)/(2|^j) - (a+(a-s)/(2|^n)) = a + (a-s)/(2|^j) - a - (a-s)/(2|^n) by XCMPLX_1:36 .= a + (a-s)/(2|^j) +- a - (a-s)/(2|^n) by XCMPLX_0:def 8 .= a +-a + (a-s)/(2|^j) - (a-s)/(2|^n) by XCMPLX_1:1 .= 0 + (a-s)/(2|^j) - (a-s)/(2|^n) by XCMPLX_0:def 6 .= (a-s)/(2|^n*2) - (a-s)/(2|^n)/(2/2) by NEWTON:11 .= (a-s)/(2|^n*2) - (a-s)*2/(2|^n*2) by XCMPLX_1:85 .= (a-s - (a-s)*2)/(2|^n*2) by XCMPLX_1:121 .= (a-s - (2*a-2*s))/(2|^n*2) by XCMPLX_1:40 .= (a-s-2*a+2*s)/(2|^n*2) by XCMPLX_1:37 .= (a-2*a-s+2*s)/(2|^n*2) by XCMPLX_1:21 .= (-a-s+2*s)/(2|^n*2) by XCMPLX_1:187 .= (-a+-s+2*s)/(2|^n*2) by XCMPLX_0:def 8 .= (-a+(-s+2*s))/(2|^n*2) by XCMPLX_1:1 .= (-a+s)/(2|^n*2) by XCMPLX_1:184 .= (s-a)/(2|^n*2) by XCMPLX_0:def 8; then 0 > a+(a-s)/(2|^j) - (a+(a-s)/(2|^n)) by A7,A8,REAL_2:128; then N-bound L~Cage(C,n+1) < N-bound L~Cage(C,n) by A6,SQUARE_1:12; hence thesis by A4,A5,AXIOMS:22,REAL_1:def 5; end; for n being Nat holds P[n] from Ind(A2,A3); hence thesis by A1; end; definition let C be connected compact non vertical non horizontal Subset of TOP-REAL 2, n be Nat; cluster Cl RightComp Cage(C,n) -> compact; coherence by GOBRD14:42; end; theorem Th8: N-min C in RightComp Cage(C,n) proof set f = Cage(C,n), G = Gauge(C,n); A1: N-min C in C by SPRECT_1:13; C misses L~f by Th5; then C /\ L~f = {} by XBOOLE_0:def 7; then A2: not N-min C in L~f by A1,XBOOLE_0:def 3; RightComp f misses L~f by SPRECT_3:42; then A3: RightComp f /\ L~f = {} by XBOOLE_0:def 7; consider k being Nat such that A4: 1 <= k & k+1 <= len G and A5: f/.1 = G*(k,width G) and A6: f/.2 = G*(k+1,width G) and A7: N-min C in cell(G,k,width G-'1) and N-min C <> G*(k,width G-'1) by JORDAN9:def 1; A8: f is_sequence_on G by JORDAN9:def 1; L~f <> {}; then A9: 1+1 <= len f by GOBRD14:8; A10: len G = width G by JORDAN8:def 1; A11: 1 <= k+1 by NAT_1:29; then A12: 1 <= len G by A4,AXIOMS:22; A13: k < len G by A4,NAT_1:38; then [k,len G] in Indices G & [k+1,len G] in Indices G by A4,A10,A11,A12,GOBOARD7:10; then A14: cell(G,k,len G-'1) = right_cell(f,1,G) by A5,A6,A8,A9,A10,GOBRD13:25; right_cell(f,1,G) c= right_cell(f,1) by A8,A9,GOBRD13:34; then A15: Int right_cell(f,1,G) c= Int right_cell(f,1) by TOPS_1:48; Int right_cell(f,1) c= RightComp f by GOBOARD9:def 2; then A16: Int cell(G,k,len G-'1) c= RightComp f by A14,A15,XBOOLE_1:1; RightComp f c= RightComp f \/ L~f by XBOOLE_1:7; then A17: Int cell(G,k,len G-'1) c= RightComp f \/ L~f by A16,XBOOLE_1:1; A18: right_cell(f,1,G) is closed by A8,A9,GOBRD13:31; A19: Fr cell(G,k,len G-'1) c= RightComp f \/ L~f proof let q be set; assume A20: q in Fr cell(G,k,len G-'1); then reconsider s = q as Point of TOP-REAL 2; 4 <= len G by JORDAN8:13; then 4 - 1 <= len G - 1 by REAL_1:92; then 0 <= len G - 1 by AXIOMS:22; then A21: len G-'1 = len G - 1 by BINARITH:def 3; A22: len G - 1 < len G - 0 by REAL_1:92; then Int cell(G,k,len G-'1) <> {} by A10,A13,A21,GOBOARD9:17; then consider p being set such that A23: p in Int cell(G,k,len G-'1) by XBOOLE_0:def 1; reconsider p as Point of TOP-REAL 2 by A23; per cases; suppose q in L~f; hence thesis by XBOOLE_0:def 2; suppose A24: not q in L~f; A25: LSeg(p,s) c= (L~f)` proof let a be set; assume A26: a in LSeg(p,s); then reconsider b = a as Point of TOP-REAL 2; 3 <= len G-'1 by GOBRD14:17; then A27: 1 <= len G-'1 by AXIOMS:22; then A28: Int cell(G,k,len G-'1) = { |[x,y]| where x, y is Real: G*(k,1)`1 < x & x < G*(k+1,1)`1 & G*(1,len G-'1)`2 < y & y < G*(1,len G-'1+1)`2 } by A4,A10,A13,A21,A22,GOBOARD6:29; A29: b = |[b`1,b`2]| by EUCLID:57; consider x, y being Real such that A30: p = |[x,y]| and A31: G*(k,1)`1 < x & x < G*(k+1,1)`1 & G*(1,len G-'1)`2 < y & y < G*(1,len G-'1+1)`2 by A23,A28; Fr cell(G,k,len G-'1) c= cell(G,k,len G-'1) by A14,A18,TOPS_1:69; then A32: q in cell(G,k,len G-'1) by A20; cell(G,k,len G-'1) = { |[m,o]| where m, o is Real: G*(k,1)`1 <= m & m <= G*(k+1,1)`1 & G*(1,len G-'1)`2 <= o & o <= G*(1,len G-'1+1)`2 } by A4,A10,A13,A21,A22,A27,GOBRD11:32; then consider m, o being Real such that A33: s = |[m,o]| and A34: G*(k,1)`1 <= m & m <= G*(k+1,1)`1 & G*(1,len G-'1)`2 <= o & o <= G*(1,len G-'1+1)`2 by A32; A35: s`1 = m & s`2 = o & p`1 = x & p`2 = y by A30,A33,EUCLID:56; now per cases; case b = s; hence a in (L~f)` by A24,SUBSET_1:50; case A36: b <> s; now per cases by REAL_1:def 5; case s`1 < p`1 & s`2 < p`2; then s`1 < b`1 & b`1 <= p`1 & s`2 < b`2 & b`2 <= p`2 by A26,A36,TOPREAL6:37,38; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 < p`1 & s`2 > p`2; then s`1 < b`1 & b`1 <= p`1 & p`2 <= b`2 & b`2 < s`2 by A26,A36,TOPREAL6:37,38; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 < p`1 & s`2 = p`2; then s`1 < b`1 & b`1 <= p`1 & p`2 = b`2 & b`2 = s`2 by A26,A36,GOBOARD7:6,TOPREAL6:37; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 > p`1 & s`2 < p`2; then s`1 > b`1 & b`1 >= p`1 & s`2 < b`2 & b`2 <= p`2 by A26,A36,TOPREAL6:37,38; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 > p`1 & s`2 > p`2; then s`1 > b`1 & b`1 >= p`1 & s`2 > b`2 & b`2 >= p`2 by A26,A36,TOPREAL6:37,38; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 > p`1 & s`2 = p`2; then s`1 > b`1 & b`1 >= p`1 & s`2 = b`2 & b`2 = p`2 by A26,A36,GOBOARD7:6,TOPREAL6:37; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 = p`1 & s`2 > p`2; then s`1 = b`1 & b`1 = p`1 & s`2 > b`2 & b`2 >= p`2 by A26,A36,GOBOARD7:5,TOPREAL6:38; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 = p`1 & s`2 < p`2; then s`1 = b`1 & b`1 = p`1 & s`2 < b`2 & b`2 <= p`2 by A26,A36,GOBOARD7:5,TOPREAL6:38; then G*(k,1)`1 < b`1 & b`1 < G*(k+1,1)`1 & G*(1,len G-'1)`2 < b`2 & b`2 < G*(1,len G-'1+1)`2 by A31,A34,A35,AXIOMS:22; hence b in Int cell(G,k,len G-'1) by A28,A29; case s`1 = p`1 & s`2 = p`2; then p = s by TOPREAL3:11; then LSeg(p,s) = {p} by TOPREAL1:7; hence b in Int cell(G,k,len G-'1) by A23,A26,TARSKI:def 1; end; then not b in L~f by A3,A16,XBOOLE_0:def 3; hence a in (L~f)` by SUBSET_1:50; end; hence a in (L~f)`; end; A37: RightComp f is_a_component_of (L~f)` by GOBOARD9:def 2; A38: {p} c= RightComp f by A16,A23,ZFMISC_1:37; {p} meets LSeg(p,s) proof now take a = p; thus a in {p} & a in LSeg(p,s) by TARSKI:def 1,TOPREAL1:6; end; hence thesis by XBOOLE_0:3; end; then A39: LSeg(p,s) c= RightComp f by A25,A37,A38,GOBOARD9:6; s in LSeg(p,s) by TOPREAL1:6; hence thesis by A39,XBOOLE_0:def 2; end; A40: Int right_cell(f,1,G) c= right_cell(f,1,G) by TOPS_1:44; Fr right_cell(f,1,G) = right_cell(f,1,G) \ Int right_cell(f,1,G) by A18,TOPS_1:77; then Fr right_cell(f,1,G) \/ Int right_cell(f,1,G) = right_cell(f,1,G) by A40,XBOOLE_1:45; then right_cell(f,1,G) c= RightComp f \/ L~f by A14,A17,A19,XBOOLE_1:8; hence thesis by A2,A7,A10,A14,XBOOLE_0:def 2; end; theorem Th9: C meets RightComp Cage (C,n) proof A1: N-min C in C by SPRECT_1:13; N-min C in RightComp Cage(C,n) by Th8; then C /\ RightComp Cage (C,n) <> {} by A1,XBOOLE_0:def 3; hence thesis by XBOOLE_0:def 7; end; theorem Th10: C misses LeftComp Cage(C,n) proof set f = Cage(C,n); C misses L~f by Th5; then A1: C /\ L~f = {} by XBOOLE_0:def 7; A2: C meets RightComp f by Th9; assume A3: C meets LeftComp f; LeftComp f is_a_component_of (L~f)` by GOBOARD9:def 1; then consider L being Subset of (TOP-REAL 2)|(L~f)` such that A4: L = LeftComp f and A5: L is_a_component_of (TOP-REAL 2)|(L~f)` by CONNSP_1:def 6; RightComp f is_a_component_of (L~f)` by GOBOARD9:def 2; then consider R being Subset of (TOP-REAL 2)|(L~f)` such that A6: R = RightComp f and A7: R is_a_component_of (TOP-REAL 2)|(L~f)` by CONNSP_1:def 6; C c= the carrier of (TOP-REAL 2)|(L~f)` proof let c be set; assume c in C; then c in the carrier of TOP-REAL 2 & not c in L~f by A1,XBOOLE_0:def 3; then c in (L~f)` by SUBSET_1:50; hence thesis by JORDAN1:1; end; then reconsider C1 = C as Subset of (TOP-REAL 2)|(L~f)`; C1 is connected by CONNSP_1:24; then L = R by A2,A3,A4,A5,A6,A7,JORDAN2C:100; hence contradiction by A4,A6,SPRECT_4:7; end; theorem Th11: C c= RightComp Cage(C,n) proof set f = Cage(C,n); let c be set; assume A1: c in C; C misses L~f by Th5; then A2: C /\ L~f = {} by XBOOLE_0:def 7; C misses LeftComp f by Th10; then C /\ LeftComp f = {} by XBOOLE_0:def 7; then not c in LeftComp f & not c in L~f by A1,A2,XBOOLE_0:def 3; hence c in RightComp f by A1,GOBRD14:28; end; theorem Th12: C c= BDD L~Cage(C,n) proof A1: C c= RightComp Cage(C,n) by Th11; RightComp Cage(C,n) is_inside_component_of L~Cage(C,n) by GOBRD14:45; then RightComp Cage(C,n) c= BDD L~Cage(C,n) by JORDAN2C:26; hence thesis by A1,XBOOLE_1:1; end; theorem Th13: UBD L~Cage(C,n) c= UBD C proof set f = Cage(C,n); A1: UBD C = union {B where B is Subset of TOP-REAL 2: B is_outside_component_of C} by JORDAN2C:def 6; let x be set; assume A2: x in UBD L~f; UBD L~f = union {B where B is Subset of TOP-REAL 2: B is_outside_component_of L~f} by JORDAN2C:def 6; then consider L being set such that A3: x in L and A4: L in {B where B is Subset of TOP-REAL 2: B is_outside_component_of L~f} by A2,TARSKI:def 4; consider B being Subset of TOP-REAL 2 such that A5: L = B and A6: B is_outside_component_of L~f by A4; the carrier of TOP-REAL 2 = the carrier of Euclid 2 by TOPREAL3:13; then reconsider B1 = B as Subset of Euclid 2; B is_a_component_of (L~f)` by A6,JORDAN2C:def 4; then consider B2 being Subset of (TOP-REAL 2)|(L~f)` such that A7: B2 = B and A8: B2 is_a_component_of (TOP-REAL 2)|(L~f)` by CONNSP_1:def 6; B2 is connected by A8,CONNSP_1:def 5; then A9: B is connected by A7,CONNSP_3:34; not B is Bounded by A6,JORDAN2C:def 4; then A10: not B1 is bounded by JORDAN2C:def 2; the carrier of (TOP-REAL 2)|C` = C` by JORDAN1:1; then skl (Down(B,C`)) c= the carrier of TOP-REAL 2 by XBOOLE_1:1; then reconsider P1 = skl (Down(B,C`)) as Subset of TOP-REAL 2; RightComp f is_inside_component_of L~f by GOBRD14:45; then A11: C c= RightComp f & B1 misses RightComp f by A6,Th11,GOBRD14:5; then B1 misses C by XBOOLE_1:63; then A12: P1 is_outside_component_of C by A9,A10,JORDAN2C:71; A13: B1 /\ RightComp f = {} by A11,XBOOLE_0:def 7; A14: Down(B,C`) = B /\ C` by CONNSP_3:def 5; B c= C` proof let a be set; assume A15: a in B; then not a in C by A11,A13,XBOOLE_0:def 3; then a in (the carrier of TOP-REAL 2) \ C by A15,XBOOLE_0:def 4; hence a in C` by SUBSET_1:def 5; end; then Down(B,C`) = B by CONNSP_3:28; then Down(B,C`) is connected by A9,JORDAN2C:15; then A16: Down(B,C`) c= skl Down(B,C`) by CONNSP_3:1; not x in C by A3,A5,A11,A13,XBOOLE_0:def 3; then x in (the carrier of TOP-REAL 2) \ C by A3,A5,XBOOLE_0:def 4; then x in C` by SUBSET_1:def 5; then A17: x in B /\ C` by A3,A5,XBOOLE_0:def 3; P1 in {W where W is Subset of TOP-REAL 2: W is_outside_component_of C} by A12; hence x in UBD C by A1,A14,A16,A17,TARSKI:def 4; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; func UBD-Family C equals :Def1: { UBD L~Cage(C,n) where n is Nat : not contradiction }; coherence; func BDD-Family C equals :Def2: { Cl BDD L~Cage(C,n) where n is Nat : not contradiction }; coherence; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; redefine func UBD-Family C -> Subset-Family of TOP-REAL 2; coherence proof { UBD L~Cage(C,i) where i is Nat : not contradiction } c= bool the carrier of TOP-REAL 2 proof let x be set; assume x in { UBD L~Cage(C,i) where i is Nat : not contradiction }; then ex i being Nat st x = UBD L~Cage(C,i) & not contradiction; hence x in bool the carrier of TOP-REAL 2; end; then UBD-Family C c= bool the carrier of TOP-REAL 2 by Def1; then UBD-Family C is Subset-Family of TOP-REAL 2 by SETFAM_1:def 7; hence thesis; end; redefine func BDD-Family C -> Subset-Family of TOP-REAL 2; coherence proof { Cl BDD L~Cage(C,i) where i is Nat : not contradiction } c= bool the carrier of TOP-REAL 2 proof let x be set; assume x in { Cl BDD L~Cage(C,i) where i is Nat : not contradiction }; then ex i being Nat st x = Cl BDD L~Cage(C,i) & not contradiction; hence x in bool the carrier of TOP-REAL 2; end; then BDD-Family C c= bool the carrier of TOP-REAL 2 by Def2; then BDD-Family C is Subset-Family of TOP-REAL 2 by SETFAM_1:def 7; hence thesis; end; end; definition let C be compact non vertical non horizontal Subset of TOP-REAL 2; cluster UBD-Family C -> non empty; coherence proof consider m being Nat; { UBD L~Cage(C,i) where i is Nat : not contradiction } = UBD-Family C by Def1; then UBD L~Cage(C,m) in UBD-Family C; hence thesis; end; cluster BDD-Family C -> non empty; coherence proof consider m being Nat; { Cl BDD L~Cage(C,i) where i is Nat : not contradiction } = BDD-Family C by Def2; then Cl BDD L~Cage(C,m) in BDD-Family C; hence thesis; end; end; theorem Th14: union UBD-Family C = UBD C proof A1: UBD-Family C = { UBD L~Cage(C,n): not contradiction } by Def1; for X being set st X in UBD-Family C holds X c= UBD C proof let X be set; assume X in UBD-Family C; then ex n st X = UBD L~Cage(C,n) & not contradiction by A1; hence X c= UBD C by Th13; end; hence union UBD-Family C c= UBD C by ZFMISC_1:94; let x be set such that A2: x in UBD C; UBD C = union {B where B is Subset of TOP-REAL 2: B is_outside_component_of C} by JORDAN2C:def 6; then consider A being set such that A3: x in A and A4: A in {B where B is Subset of TOP-REAL 2: B is_outside_component_of C} by A2,TARSKI:def 4; consider B being Subset of TOP-REAL 2 such that A5: A = B and B is_outside_component_of C by A4; reconsider p = x as Point of TOP-REAL 2 by A3,A5; consider q being Point of TOP-REAL 2 such that A6: q`2 > N-bound L~Cage(C,0) and A7: p <> q by TOPREAL6:41; A8: UBD L~Cage(C,0) c= UBD C by Th13; A9: Cage(C,0)/.1 = N-min L~Cage(C,0) by JORDAN9:34; A10: UBD L~Cage(C,0) = LeftComp Cage(C,0) by GOBRD14:46; q in LeftComp Cage(C,0) by A6,A9,JORDAN2C:121; then consider P such that A11: P is_S-P_arc_joining p,q and A12: P c= UBD C by A2,A7,A8,A10,TOPREAL4:30; consider f being FinSequence of TOP-REAL 2 such that A13: f is_S-Seq and A14: P = L~f and A15: p = f/.1 and q = f/.len f by A11,TOPREAL4:def 1; reconsider f as being_S-Seq FinSequence of TOP-REAL 2 by A13; A16: L~f is non empty; TOP-REAL 2 = TopSpaceMetr Euclid 2 by EUCLID:def 8; then reconsider P1 = P, C1 = C as non empty compact Subset of TopSpaceMetr Euclid 2 by A14,A16; set d = min_dist_min(P1,C1); C is Bounded by JORDAN2C:73; then consider B being Subset of TOP-REAL 2 such that A17: B is_outside_component_of C & B = UBD C by JORDAN2C:76; UBD C is_a_component_of C` by A17,JORDAN2C:def 4; then C misses UBD C by GOBRD14:4; then P misses C by A12,XBOOLE_1:63; then d > 0 by JGRAPH_1:55; then d/2 > 0 by REAL_2:127; then consider n such that 1 < n and A18: dist(Gauge(C,n)*(1,1),Gauge(C,n)*(1,2)) < d/2 and A19: dist(Gauge(C,n)*(1,1),Gauge(C,n)*(2,1)) < d/2 by GOBRD14:21; set G = Gauge(C,n), g = Cage(C,n); 2 <= len f by SPPOL_1:2; then A20: x in P by A14,A15,JORDAN3:34; A21: now assume L~g /\ P <> {}; then consider a being set such that A22: a in L~g /\ P by XBOOLE_0:def 1; reconsider a' = a as Point of Euclid 2 by A22,TOPREAL3:13; reconsider A = a as Point of TOP-REAL 2 by A22; A23: a in L~g & a in P by A22,XBOOLE_0:def 3; then consider i such that A24: 1 <= i & i+1 <= len g and A25: a in LSeg(g,i) by SPPOL_2:13; A26: g is_sequence_on G by JORDAN9:def 1; then consider i1, j1, i2, j2 being Nat such that A27: [i1,j1] in Indices G and A28: g/.i = G*(i1,j1) and A29: [i2,j2] in Indices G and A30: g/.(i+1) = G*(i2,j2) and A31: i1 = i2 & j1+1 = j2 or i1+1 = i2 & j1 = j2 or i1 = i2+1 & j1 = j2 or i1 = i2 & j1 = j2+1 by A24,JORDAN8:6; right_cell(g,i,G) meets C by A24,JORDAN9:33; then consider c being set such that A32: c in right_cell(g,i,G) /\ C by XBOOLE_0:4; reconsider c as Point of Euclid 2 by A32,TOPREAL3:13; reconsider c' = c as Point of TOP-REAL 2 by A32; c in C by A32,XBOOLE_0:def 3; then A33: dist(a',c) >= d by A23,WEIERSTR:40; set e = E-bound C, w = W-bound C, p = N-bound C, s = S-bound C; A34: len G = width G by JORDAN8:def 1; 4 <= len G by JORDAN8:13; then A35: 1 <= len G & 1 <= width G & 1+1 <= len G & 1+1 <= width G by A34,AXIOMS:22; then [1,1] in Indices G & [1,1+1] in Indices G & [1+1,1] in Indices G by GOBOARD7:10; then A36: dist(G*(1,1),G*(1,1+1)) = (p-s)/2|^n & dist(G*(1,1),G*(1+1,1)) = (e-w)/2|^n by GOBRD14:19,20; A37: c in right_cell(g,i,G) by A32,XBOOLE_0:def 3; left_cell(g,i,G) /\ right_cell(g,i,G) = LSeg(g,i) by A24,A26,GOBRD13:30 ; then A38: a in right_cell(g,i,G) by A25,XBOOLE_0:def 3; now per cases by A31; case A39: i1 = i2 & j1+1 = j2; then A40: j1+1 <= width G by A29,GOBOARD5:1; then A41: 1 <= i1 & i1 < len G & 1 <= j1 & j1 < width G by A24,A27,A28,A29,A30,A39,Th1,GOBOARD5:1,NAT_1:38; A42: right_cell(g,i,G) = cell(G,i1,j1) by A24,A26,A27,A28,A29,A30,A39,GOBRD13:23 .= { |[r,t]| where r, t is Real : G*(i1,1)`1 <= r & r <= G*(i1+1,1)`1 & G*(1,j1)`2 <= t & t <= G*(1,j1+1)`2 } by A41,GOBRD11:32; then consider r, t being Real such that A43: c = |[r,t]| and A44: G*(i1,1)`1 <= r & r <= G*(i1+1,1)`1 & G*(1,j1)`2 <= t & t <= G*(1,j1+1)`2 by A37; consider aa, ab being Real such that A45: a = |[aa,ab]| and A46: G*(i1,1)`1 <= aa & aa <= G*(i1+1,1)`1 & G*(1,j1)`2 <= ab & ab <= G*(1,j1+1)`2 by A38,A42; A47: c'`1 = r & c'`2 = t & A`1 = aa & A`2 = ab by A43,A45,EUCLID:56; 1 <= i1+1 & i1+1 <= len G & 1 <= j1+1 by A41,NAT_1:38; then A48: [i1,1] in Indices G & [i1+1,1] in Indices G & [1,j1] in Indices G & [1,j1+1] in Indices G by A35,A40,A41,GOBOARD7:10; then A49: dist(G*(i1,1),G*(i1+1,1)) = G*(i1+1,1)`1 - G*(i1,1)`1 & dist(G*(1,j1),G*(1,j1+1)) = G*(1,j1+1)`2 - G*(1,j1)`2 by GOBRD14:15,16; dist(G*(1,j1),G*(1,j1+1)) = (p-s)/2|^n & dist(G*(i1,1),G*(i1+1,1)) = (e-w)/2|^n by A48,GOBRD14:19,20; hence dist(A,c') <= (p-s)/2|^n + (e-w)/2|^n by A44,A46,A47,A49,GOBRD14: 12; case A50: i1+1 = i2 & j1 = j2; then A51: i1+1 <= len G by A29,GOBOARD5:1; j2 > 1 by A24,A27,A28,A29,A30,A50,Th3; then A52: j2-1 > 0 by SQUARE_1:11; then A53: j2-1 = j2-'1 by BINARITH:def 3; A54: j2 <= width G by A29,GOBOARD5:1; width G - 1 < width G - 0 by REAL_1:92; then A55: 1 <= i1 & i1 < len G & 1 <= j2-'1 & j2-'1 < width G by A27,A51,A52,A53,A54,GOBOARD5:1,NAT_1:38,REAL_1:92,RLVECT_1:99; A56: right_cell(g,i,G) = cell(G,i1,j2-'1) by A24,A26,A27,A28,A29,A30,A50,GOBRD13:25 .= { |[r,t]| where r, t is Real : G*(i1,1)`1 <= r & r <= G*(i1+1,1)`1 & G*(1,j2-'1)`2 <= t & t <= G*(1,j2-'1+1)`2 } by A55,GOBRD11:32; then consider r, t being Real such that A57: c = |[r,t]| and A58: G*(i1,1)`1 <= r & r <= G*(i1+1,1)`1 & G*(1,j2-'1)`2 <= t & t <= G*(1,j2-'1+1)`2 by A37; consider aa, ab being Real such that A59: a = |[aa,ab]| and A60: G*(i1,1)`1 <= aa & aa <= G*(i1+1,1)`1 & G*(1,j2-'1)`2 <= ab & ab <= G*(1,j2-'1+1)`2 by A38,A56; A61: c'`1 = r & c'`2 = t & A`1 = aa & A`2 = ab by A57,A59,EUCLID:56; A62: 1 <= i1+1 & i1+1 <= len G & j2-'1+1 <= width G by A55,NAT_1:38; 1 <= j2-'1+1 by A55,NAT_1:38; then A63: [i1,1] in Indices G & [i1+1,1] in Indices G & [1,j2-'1] in Indices G & [1,j2-'1+1] in Indices G by A35,A55,A62,GOBOARD7:10; then A64: dist(G*(i1,1),G*(i1+1,1)) = G*(i1+1,1)`1 - G*(i1,1)`1 & dist(G*(1,j2-'1),G*(1,j2-'1+1)) = G*(1,j2-'1+1)`2 - G*(1,j2-'1)`2 by GOBRD14:15,16; dist(G*(1,j2-'1),G*(1,j2-'1+1)) = (p-s)/2|^n & dist(G*(i1,1),G*(i1+1,1)) = (e-w)/2|^n by A63,GOBRD14:19,20; hence dist(A,c') <= (p-s)/2|^n + (e-w)/2|^n by A58,A60,A61,A64,GOBRD14: 12; case A65: i1 = i2+1 & j1 = j2; then i2+1 <= len G by A27,GOBOARD5:1; then A66: 1 <= i2 & i2 < len G & 1 <= j1 & j1 < width G by A24,A27,A28,A29,A30,A65,Th4,GOBOARD5:1,NAT_1:38; A67: right_cell(g,i,G) = cell(G,i2,j1) by A24,A26,A27,A28,A29,A30,A65,GOBRD13:27 .= { |[r,t]| where r, t is Real : G*(i2,1)`1 <= r & r <= G*(i2+1,1)`1 & G*(1,j1)`2 <= t & t <= G*(1,j1+1)`2 } by A66,GOBRD11:32; then consider r, t being Real such that A68: c = |[r,t]| and A69: G*(i2,1)`1 <= r & r <= G*(i2+1,1)`1 & G*(1,j1)`2 <= t & t <= G*(1,j1+1)`2 by A37; consider aa, ab being Real such that A70: a = |[aa,ab]| and A71: G*(i2,1)`1 <= aa & aa <= G*(i2+1,1)`1 & G*(1,j1)`2 <= ab & ab <= G*(1,j1+1)`2 by A38,A67; A72: c'`1 = r & c'`2 = t & A`1 = aa & A`2 = ab by A68,A70,EUCLID:56; A73: 1 <= i2+1 & i2+1 <= len G & j1+1 <= width G by A66,NAT_1:38; 1 <= j1+1 by NAT_1:37; then A74: [i2,1] in Indices G & [i2+1,1] in Indices G & [1,j1] in Indices G & [1,j1+1] in Indices G by A35,A66,A73,GOBOARD7:10; then A75: dist(G*(i2,1),G*(i2+1,1)) = G*(i2+1,1)`1 - G*(i2,1)`1 & dist(G*(1,j1),G*(1,j1+1)) = G*(1,j1+1)`2 - G*(1,j1)`2 by GOBRD14:15,16; dist(G*(1,j1),G*(1,j1+1)) = (p-s)/2|^n & dist(G*(i2,1),G*(i2+1,1)) = (e-w)/2|^n by A74,GOBRD14:19,20; hence dist(A,c') <= (p-s)/2|^n + (e-w)/2|^n by A69,A71,A72,A75,GOBRD14: 12; case A76: i1 = i2 & j1 = j2+1; then A77: j2+1 <= width G by A27,GOBOARD5:1; i1 > 1 by A24,A27,A28,A29,A30,A76,Th2; then A78: i1-1 > 0 by SQUARE_1:11; then A79: i1-1 = i1-'1 by BINARITH:def 3; A80: i1 <= len G by A27,GOBOARD5:1; len G - 1 < len G - 0 by REAL_1:92; then A81: 1 <= i1-'1 & i1-'1 < len G & 1 <= j2 & j2 < width G by A29,A77,A78,A79,A80,GOBOARD5:1,NAT_1:38,REAL_1:92,RLVECT_1:99; A82: right_cell(g,i,G) = cell(G,i1-'1,j2) by A24,A26,A27,A28,A29,A30,A76,GOBRD13:29 .= { |[r,t]| where r, t is Real : G*(i1-'1,1)`1 <= r & r <= G*(i1-'1+1,1)`1 & G*(1,j2)`2 <= t & t <= G*(1,j2+1)`2 } by A81,GOBRD11:32; then consider r, t being Real such that A83: c = |[r,t]| and A84: G*(i1-'1,1)`1 <= r & r <= G*(i1-'1+1,1)`1 & G*(1,j2)`2 <= t & t <= G*(1,j2+1)`2 by A37; consider aa, ab being Real such that A85: a = |[aa,ab]| and A86: G*(i1-'1,1)`1 <= aa & aa <= G*(i1-'1+1,1)`1 & G*(1,j2)`2 <= ab & ab <= G*(1,j2+1)`2 by A38,A82; A87: c'`1 = r & c'`2 = t & A`1 = aa & A`2 = ab by A83,A85,EUCLID:56; 1 <= i1-'1+1 & i1-'1+1 <= len G & 1 <= j2+1 by A81,NAT_1:38; then A88: [i1-'1,1] in Indices G & [i1-'1+1,1] in Indices G & [1,j2] in Indices G & [1,j2+1] in Indices G by A35,A77,A81,GOBOARD7:10; then A89: dist(G*(i1-'1,1),G*(i1-'1+1,1)) = G*(i1-'1+1,1)`1 - G*(i1-'1,1)`1 & dist(G*(1,j2),G*(1,j2+1)) = G*(1,j2+1)`2 - G*(1,j2)`2 by GOBRD14:15,16; dist(G*(1,j2),G*(1,j2+1)) = (p-s)/2|^n & dist(G*(i1-'1,1),G* (i1-'1+1,1)) = (e-w)/2|^n by A88,GOBRD14:19,20; hence dist(A,c') <= (p-s)/2|^n + (e-w)/2|^n by A84,A86,A87,A89,GOBRD14: 12; end; then A90: dist(a',c) <= (p-s)/2|^n + (e-w)/2|^n by GOBRD14:def 1; (p-s)/2|^n + (e-w)/2|^n < d/2 + d/2 by A18,A19,A36,REAL_1:67; then (p-s)/2|^n + (e-w)/2|^n < d by XCMPLX_1:66; hence contradiction by A33,A90,AXIOMS:22; end; L~g is Bounded by JORDAN2C:73; then consider B being Subset of TOP-REAL 2 such that A91: B is_outside_component_of L~g and A92: B = UBD L~g by JORDAN2C:76; consider E being Subset of (TOP-REAL 2)|(L~g)` such that A93: E = B & E is_a_component_of (TOP-REAL 2)|(L~g)` and not E is bounded Subset of Euclid 2 by A91,JORDAN2C:18; A94: P c= (L~g)` proof let a be set; assume A95: a in P; then not a in L~g by A21,XBOOLE_0:def 3; hence thesis by A95,SUBSET_1:50; end; A96: P is_an_arc_of p,q by A11,A14,A16,TOPREAL4:3; then A97: P is connected by JORDAN6:11; A98: UBD L~g is_a_component_of (L~g)` by A92,A93,CONNSP_1:def 6; A99: g/.1 = N-min L~g by JORDAN9:34; 0 < n or 0 = n by NAT_1:18; then N-bound L~(Cage(C,0)) >= N-bound L~g by Th7; then q`2 > N-bound L~g by A6,AXIOMS:22; then q in LeftComp g by A99,JORDAN2C:121; then q in UBD L~g by GOBRD14:46; then A100: {q} c= UBD L~g by ZFMISC_1:37; {q} meets P proof now take a = q; thus a in {q} & a in P by A96,TARSKI:def 1,TOPREAL1:4; end; hence thesis by XBOOLE_0:3; end; then A101: P c= UBD L~g by A94,A97,A98,A100,GOBOARD9:6; UBD L~g in UBD-Family C by A1; hence x in union UBD-Family C by A20,A101,TARSKI:def 4; end; theorem Th15: C c= meet BDD-Family C proof A1: BDD-Family C = { Cl BDD L~Cage(C,k) where k is Nat : not contradiction } by Def2; for Z being set st Z in BDD-Family C holds C c= Z proof let Z be set; assume Z in BDD-Family C; then consider k being Nat such that A2: Z = Cl BDD L~Cage(C,k) by A1; A3: C c= BDD L~Cage(C,k) by Th12; BDD L~Cage(C,k) c= Cl BDD L~Cage(C,k) by PRE_TOPC:48; hence thesis by A2,A3,XBOOLE_1:1; end; hence thesis by SETFAM_1:6; end; theorem Th16: BDD C misses LeftComp Cage(C,n) proof set f = Cage(C,n); assume BDD C /\ LeftComp f <> {}; then consider x being Point of TOP-REAL 2 such that A1: x in BDD C /\ LeftComp f by SUBSET_1:10; A2: x in BDD C & x in LeftComp f by A1,XBOOLE_0:def 3; A3: UBD-Family C = { UBD L~Cage(C,k) where k is Nat : not contradiction } by Def1; BDD C misses UBD C by JORDAN2C:28; then BDD C /\ UBD C = {} by XBOOLE_0:def 7; then not x in UBD C by A2,XBOOLE_0:def 3; then A4: not x in union UBD-Family C by Th14; UBD L~f in { UBD L~Cage(C,k) where k is Nat : not contradiction }; then not x in UBD L~f by A3,A4,TARSKI:def 4; hence contradiction by A2,GOBRD14:46; end; theorem Th17: BDD C c= RightComp Cage(C,n) proof set f = Cage(C,n); let x be set; assume A1: x in BDD C; A2: UBD-Family C = { UBD L~Cage(C,k) where k is Nat : not contradiction } by Def1; BDD C misses UBD C by JORDAN2C:28; then BDD C /\ UBD C = {} by XBOOLE_0:def 7; then not x in UBD C by A1,XBOOLE_0:def 3; then A3: not x in union UBD-Family C by Th14; UBD L~f in { UBD L~Cage(C,k) where k is Nat : not contradiction }; then A4: not x in UBD L~Cage(C,n) by A2,A3,TARSKI:def 4; A5: UBD L~f = union {E where E is Subset of TOP-REAL 2: E is_outside_component_of L~f} by JORDAN2C:def 6; LeftComp f is_outside_component_of L~f by GOBRD14:44; then LeftComp f in {E where E is Subset of TOP-REAL 2: E is_outside_component_of L~f}; then A6: not x in LeftComp f by A4,A5,TARSKI:def 4; A7: L~f = (Cl LeftComp f) \ LeftComp f by GOBRD14:30; now assume x in Cl LeftComp f; then BDD C meets LeftComp f by A1,PRE_TOPC:def 13; hence contradiction by Th16; end; then not x in L~f by A7,XBOOLE_0:def 4; hence x in RightComp f by A1,A6,GOBRD14:28; end; theorem Th18: P is_inside_component_of C implies P misses L~Cage(C,n) proof set f = Cage(C,n); assume A1: P is_inside_component_of C; assume P /\ L~f <> {}; then consider x being Point of TOP-REAL 2 such that A2: x in P /\ L~f by SUBSET_1:10; A3: x in P & x in L~f by A2,XBOOLE_0:def 3; P c= BDD C by A1,JORDAN2C:26; then A4: x in BDD C by A3; BDD C c= RightComp f by Th17; hence contradiction by A3,A4,GOBRD14:28; end; theorem Th19: BDD C misses L~Cage(C,n) proof A1: BDD C = union {B where B is Subset of TOP-REAL 2: B is_inside_component_of C} by JORDAN2C:def 5; assume not thesis; then consider x being set such that A2: x in BDD C /\ L~Cage(C,n) by XBOOLE_0:4; x in BDD C by A2,XBOOLE_0:def 3; then consider Z being set such that A3: x in Z & Z in {B where B is Subset of TOP-REAL 2: B is_inside_component_of C} by A1,TARSKI:def 4; consider B being Subset of TOP-REAL 2 such that A4: Z = B & B is_inside_component_of C by A3; B misses L~Cage(C,n) by A4,Th18; then A5: B /\ L~Cage(C,n) = {} by XBOOLE_0:def 7; x in L~Cage(C,n) by A2,XBOOLE_0:def 3; hence thesis by A3,A4,A5,XBOOLE_0:def 3; end; theorem Th20: COMPLEMENT UBD-Family C = BDD-Family C proof A1: BDD-Family C = { Cl BDD L~Cage(C,k) where k is Nat : not contradiction } by Def2; A2: UBD-Family C = { UBD L~Cage(C,n): not contradiction } by Def1; for P being Subset of TOP-REAL 2 holds P in BDD-Family C iff P` in UBD-Family C proof let P being Subset of TOP-REAL 2; thus P in BDD-Family C implies P` in UBD-Family C proof assume P in BDD-Family C; then consider k such that A3: P = Cl BDD L~Cage(C,k) by A1; P = Cl RightComp Cage(C,k) by A3,GOBRD14:47; then A4: P = (RightComp Cage(C,k)) \/ L~Cage(C,k) by GOBRD14:31; A5: L~Cage(C,k) misses LeftComp Cage(C,k) by SPRECT_3:43; RightComp Cage(C,k) misses LeftComp Cage(C,k) by GOBRD14:24; then A6: P misses LeftComp Cage(C,k) by A4,A5,XBOOLE_1:70; A7: P \/ LeftComp Cage(C,k) = the carrier of TOP-REAL 2 by A4,GOBRD14:25; P` /\ (LeftComp Cage(C,k))` = (P \/ LeftComp Cage(C,k))` by SUBSET_1: 29 .= ([#]the carrier of TOP-REAL 2)` by A7,SUBSET_1:def 4 .= {}the carrier of TOP-REAL 2 by SUBSET_1:21; then P` misses (LeftComp Cage(C,k))` by XBOOLE_0:def 7; then P` = LeftComp Cage(C,k) by A6,SUBSET_1:46; then P` = UBD L~Cage(C,k) by GOBRD14:46; hence P` in UBD-Family C by A2; end; assume P` in UBD-Family C; then consider k such that A8: P` = UBD L~Cage(C,k) by A2; A9: P` = LeftComp Cage(C,k) by A8,GOBRD14:46; then A10: P` misses RightComp Cage(C,k) by GOBRD14:24; P` misses L~Cage(C,k) by A9,SPRECT_3:43; then P` misses (RightComp Cage(C,k)) \/ L~Cage(C,k) by A10,XBOOLE_1:70; then A11: P` misses Cl RightComp Cage(C,k) by GOBRD14:31; A12: P` \/ ((RightComp Cage(C,k)) \/ L~Cage(C,k)) = the carrier of TOP-REAL 2 by A9,GOBRD14:25; P`` /\ (Cl RightComp Cage(C,k))` = (P` \/ (Cl RightComp Cage(C,k)))` by SUBSET_1:29 .= (P` \/ ((RightComp Cage(C,k)) \/ L~Cage(C,k)))` by GOBRD14:31 .= ([#]the carrier of TOP-REAL 2)` by A12,SUBSET_1:def 4 .= {}the carrier of TOP-REAL 2 by SUBSET_1:21; then P`` misses (Cl RightComp Cage(C,k))` by XBOOLE_0:def 7; then P`` = Cl RightComp Cage(C,k) by A11,SUBSET_1:46; then P = Cl BDD L~Cage(C,k) by GOBRD14:47; hence P in BDD-Family C by A1; end; hence thesis by SETFAM_1:def 8; end; theorem meet BDD-Family C = C \/ BDD C proof (BDD C) misses (UBD C) by JORDAN2C:28; then A1: (BDD C) /\ (UBD C) = {} by XBOOLE_0:def 7; A2: UBD-Family C = { UBD L~Cage(C,n) where n is Nat : not contradiction } by Def1; A3: BDD-Family C = { Cl BDD L~Cage(C,n) where n is Nat : not contradiction } by Def2; thus meet BDD-Family C c= C \/ BDD C proof let x be set; assume A4: x in meet BDD-Family C; COMPLEMENT UBD-Family C = BDD-Family C by Th20; then ([#] the carrier of TOP-REAL 2) \ union UBD-Family C = meet BDD-Family C by SETFAM_1:47; then not x in union UBD-Family C by A4,XBOOLE_0:def 4; then A5: not x in UBD C by Th14; per cases; suppose not x in C; then A6: x in C` by A4,SUBSET_1:50; BDD C \/ UBD C = C` by JORDAN2C:31; then x in BDD C by A5,A6,XBOOLE_0:def 2; hence x in C \/ BDD C by XBOOLE_0:def 2; suppose x in C; hence x in C \/ BDD C by XBOOLE_0:def 2; end; A7: BDD C c= meet BDD-Family C proof let x be set; assume A8: x in BDD C; then not x in UBD C by A1,XBOOLE_0:def 3; then A9: not x in union UBD-Family C by Th14; for Y being set st Y in BDD-Family C holds x in Y proof let Y be set; assume Y in BDD-Family C; then consider n such that A10: Y = Cl BDD L~Cage(C,n) and not contradiction by A3; A11: UBD L~Cage(C,n) = union{B where B is Subset of TOP-REAL 2: B is_outside_component_of L~Cage(C,n)} by JORDAN2C:def 6; A12: BDD L~Cage(C,n) = union{B where B is Subset of TOP-REAL 2: B is_inside_component_of L~Cage(C,n)} by JORDAN2C:def 5; UBD L~Cage(C,n) in UBD-Family C by A2; then A13: not x in UBD L~Cage(C,n) by A9,TARSKI:def 4; LeftComp Cage(C,n) is_outside_component_of L~Cage(C,n) by GOBRD14:44; then LeftComp Cage(C,n) in {B where B is Subset of TOP-REAL 2: B is_outside_component_of L~Cage(C,n)}; then A14: not x in LeftComp Cage(C,n) by A11,A13,TARSKI:def 4; BDD C misses L~Cage(C,n) by Th19; then BDD C /\ L~Cage(C,n) = {} by XBOOLE_0:def 7; then not x in L~Cage(C,n) by A8,XBOOLE_0:def 3; then A15: x in RightComp Cage(C,n) by A8,A14,GOBRD14:28; RightComp Cage(C,n) is_inside_component_of L~Cage(C,n) by GOBRD14:45; then RightComp Cage(C,n) in {B where B is Subset of TOP-REAL 2: B is_inside_component_of L~Cage(C,n)}; then A16: x in BDD L~Cage(C,n) by A12,A15,TARSKI:def 4; BDD L~Cage(C,n) c= Cl BDD L~Cage(C,n) by PRE_TOPC:48; hence x in Y by A10,A16; end; hence x in meet BDD-Family C by SETFAM_1:def 1; end; C c= meet BDD-Family C by Th15; hence thesis by A7,XBOOLE_1:8; end;