Copyright (c) 1995 Association of Mizar Users
environ vocabulary PRE_TOPC, EUCLID, SEQM_3, GOBOARD5, FINSEQ_1, GOBOARD2, TREES_1, TOPREAL1, ARYTM_3, BOOLE, TOPS_1, ARYTM_1, MCART_1, GOBOARD1, RELAT_1, MATRIX_1, ABSVALUE, FINSEQ_4; notation TARSKI, XBOOLE_0, XREAL_0, REAL_1, NAT_1, ABSVALUE, BINARITH, FINSEQ_1, FINSEQ_4, MATRIX_1, STRUCT_0, PRE_TOPC, TOPS_1, EUCLID, TOPREAL1, GOBOARD1, GOBOARD2, GOBOARD5; constructors TOPS_1, GROUP_1, GOBOARD5, GOBOARD2, SEQM_3, REAL_1, BINARITH, FINSEQ_4, MEMBERED; clusters STRUCT_0, GOBOARD5, RELSET_1, GOBOARD2, EUCLID, ARYTM_3, MEMBERED; requirements REAL, NUMERALS, SUBSET, ARITHM; theorems GOBOARD5, EUCLID, GOBOARD1, RLVECT_1, REAL_1, AXIOMS, TOPREAL3, REAL_2, TOPREAL1, GOBOARD2, FINSEQ_3, NAT_1, AMI_5, GOBOARD6, GOBOARD7, SPPOL_2, XBOOLE_0, XBOOLE_1, ZFMISC_1, XCMPLX_0, XCMPLX_1; begin reserve i,j,k,i1,j1 for Nat, p for Point of TOP-REAL 2, x for set; reserve f for non constant standard special_circular_sequence; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= i & i+1 <= len GoB f & 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+1,j) & f/.(k+2) = (GoB f)*(i+1,j+2) or f/.(k+2) = (GoB f)*(i+1,j) & f/.k = (GoB f)*(i+1,j+2)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= i & i+1 <= len GoB f and A7: 1 <= j & j+2 <= width GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+1,j) & f/.(k+2) = (GoB f)*(i+1,j+2) or f/.(k+2) = (GoB f)*(i+1,j) & f/.k = (GoB f)*(i+1,j+2)); j < j+2 by REAL_1:69; then A10: j <= width GoB f by A7,AXIOMS:22; j+1 <= j+2 by AXIOMS:24; then A11: 1 <= j+1 & j+1 <= width GoB f by A7,AXIOMS:22,NAT_1:29; A12: j+1+1 = j+(1+1) by XCMPLX_1:1; then A13: j+1 < width GoB f by A7,NAT_1:38; A14: i < len GoB f by A6,NAT_1:38; assume A15: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1+1))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A6,A7,A12,A13,A14,GOBOARD6:67; then A16: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A12,A15,XBOOLE_1:63 ; A17: L~f misses Int cell(GoB f,i,j) by A10,A14,GOBOARD7:14; L~f misses Int cell(GoB f,i,j+1) by A11,A14,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg(f/.(k+1),(GoB f)*(i,j+1)) = LSeg(f,k0) by A6,A8,A11,GOBOARD7:42; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A13,A14,A18,A19,A20,GOBOARD7:62; end; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= i & i+2 <= len GoB f & 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+2,j+1) & f/.(k+2) = (GoB f)*(i+1,j+2) or f/.(k+2) = (GoB f)*(i+2,j+1) & f/.k = (GoB f)*(i+1,j+2)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= i & i+2 <= len GoB f and A7: 1 <= j & j+2 <= width GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+2,j+1) & f/.(k+2) = (GoB f)*(i+1,j+2) or f/.(k+2) = (GoB f)*(i+2,j+1) & f/.k = (GoB f)*(i+1,j+2)); j < j+2 by REAL_1:69; then A10: j < width GoB f by A7,AXIOMS:22; j+1 <= j+2 by AXIOMS:24; then A11: 1 <= j+1 & j+1 <= width GoB f by A7,AXIOMS:22,NAT_1:29; i+1+1 = i+(1+1) by XCMPLX_1:1; then A12: i+1 < len GoB f by A6,NAT_1:38; A13: j+1+1 = j+(1+1) by XCMPLX_1:1; then A14: j+1 < width GoB f by A7,NAT_1:38; A15: i < len GoB f by A12,NAT_1:38; assume A16: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1+1))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A6,A7,A13,A14,A15,GOBOARD6:67; then A17: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A13,A16,XBOOLE_1:63 ; A18: L~f misses Int cell(GoB f,i,j) by A10,A15,GOBOARD7:14; L~f misses Int cell(GoB f,i,j+1) by A11,A15,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) by A18,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A17,XBOOLE_1:70; then 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A19: LSeg( f/.(k+1),(GoB f)*(i,j+1)) = LSeg(f,k0) by A6,A8,A11,A12,GOBOARD7:42; A20: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A21: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A8,A9,A11,A12,A13,A14,A19,A20,A21,GOBOARD7:63; end; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= i & i+2 <= len GoB f & 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+2,j+1) & f/.(k+2) = (GoB f)*(i+1,j) or f/.(k+2) = (GoB f)*(i+2,j+1) & f/.k = (GoB f)*(i+1,j)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= i & i+2 <= len GoB f and A7: 1 <= j & j+2 <= width GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+2,j+1) & f/.(k+2) = (GoB f)*(i+1,j) or f/.(k+2) = (GoB f)*(i+2,j+1) & f/.k = (GoB f)*(i+1,j)); j < j+2 by REAL_1:69; then A10: j < width GoB f by A7,AXIOMS:22; j+1 <= j+2 by AXIOMS:24; then A11: 1 <= j+1 & j+1 <= width GoB f by A7,AXIOMS:22,NAT_1:29; i+1+1 = i+(1+1) by XCMPLX_1:1; then A12: i+1 < len GoB f by A6,NAT_1:38; j+1+1 = j+(1+1) by XCMPLX_1:1; then A13: j+1 < width GoB f by A7,NAT_1:38; A14: i < len GoB f by A12,NAT_1:38; assume A15: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A6,A7,A13,A14,GOBOARD6:67; then A16: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A15,XBOOLE_1:63; A17: L~f misses Int cell(GoB f,i,j) by A10,A14,GOBOARD7:14; L~f misses Int cell(GoB f,i,j+1) by A11,A14,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg( f/.(k+1),(GoB f)*(i,j+1)) = LSeg(f,k0) by A6,A8,A11,A12,GOBOARD7:42; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A10,A12,A18,A19,A20,GOBOARD7:64; end; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= i & i+1 <= len GoB f & 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(i,j+1) & (f/.k = (GoB f)*(i,j) & f/.(k+2) = (GoB f)*(i,j+2) or f/.(k+2) = (GoB f)*(i,j) & f/.k = (GoB f)*(i,j+2)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= i & i+1 <= len GoB f and A7: 1 <= j & j+2 <= width GoB f and A8: f/.(k+1) = (GoB f)*(i,j+1) and A9: (f/.k = (GoB f)*(i,j) & f/.(k+2) = (GoB f)*(i,j+2) or f/.(k+2) = (GoB f)*(i,j) & f/.k = (GoB f)*(i,j+2)); j < j+2 by REAL_1:69; then A10: j <= width GoB f by A7,AXIOMS:22; j+1 <= j+2 by AXIOMS:24; then A11: 1 <= j+1 & j+1 <= width GoB f by A7,AXIOMS:22,NAT_1:29; j+1+1 = j+(1+1) by XCMPLX_1:1; then A12: j+1 < width GoB f by A7,NAT_1:38; A13: i < len GoB f by A6,NAT_1:38; assume A14: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A6,A7,A12,A13,GOBOARD6:67; then A15: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) \/ { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A14,XBOOLE_1:63; A16: L~f misses Int cell(GoB f,i,j) by A10,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i,j+1) by A11,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i,j+1) by A16,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) } by A15,XBOOLE_1:70; then 1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A17: LSeg(f/.(k+1),(GoB f)*(i+1,j+1)) = LSeg(f,k0) by A6,A8,A11,GOBOARD7:42; A18: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A19: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A12,A13,A17,A18,A19,GOBOARD7:61; end; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= i & i+2 <= len GoB f & 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i,j+1) & f/.(k+2) = (GoB f)*(i+1,j+2) or f/.(k+2) = (GoB f)*(i,j+1) & f/.k = (GoB f)*(i+1,j+2)) holds LSeg(1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= i & i+2 <= len GoB f and A7: 1 <= j & j+2 <= width GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i,j+1) & f/.(k+2) = (GoB f)*(i+1,j+2) or f/.(k+2) = (GoB f)*(i,j+1) & f/.k = (GoB f)*(i+1,j+2)); j < j+2 by REAL_1:69; then A10: j < width GoB f by A7,AXIOMS:22; j+1 <= j+2 by AXIOMS:24; then A11: 1 <= j+1 & j+1 <= width GoB f by A7,AXIOMS:22,NAT_1:29; A12: i+1+1 = i+(1+1) by XCMPLX_1:1; then A13: i+1 < len GoB f by A6,NAT_1:38; A14: j+1+1 = j+(1+1) by XCMPLX_1:1; then A15: j+1 < width GoB f by A7,NAT_1:38; A16: 1 <= i+1 by NAT_1:29; assume A17: LSeg(1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) c= Int cell(GoB f,i+1,j) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+1)) } by A7,A12,A13,A15,A16,GOBOARD6:67; then A18: L~f meets Int cell(GoB f,i+1,j) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)* (i+2,j+1)) } by A17,XBOOLE_1:63; A19: L~f misses Int cell(GoB f,i+1,j) by A10,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j+1) by A11,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i+1,j) \/ Int cell(GoB f,i+1,j+1) by A19,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+1)) } by A18,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A20: LSeg(f/.(k+1),(GoB f)*(i+2,j+1)) = LSeg(f,k0) by A6,A8,A11,A12,A16,GOBOARD7:42; A21: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A22: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A8,A9,A11,A13,A14,A15,A20,A21,A22,GOBOARD7:63; end; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= i & i+2 <= len GoB f & 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i,j+1) & f/.(k+2) = (GoB f)*(i+1,j) or f/.(k+2) = (GoB f)*(i,j+1) & f/.k = (GoB f)*(i+1,j)) holds LSeg(1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= i & i+2 <= len GoB f and A7: 1 <= j & j+2 <= width GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i,j+1) & f/.(k+2) = (GoB f)*(i+1,j) or f/.(k+2) = (GoB f)*(i,j+1) & f/.k = (GoB f)*(i+1,j)); j < j+2 by REAL_1:69; then A10: j < width GoB f by A7,AXIOMS:22; j+1 <= j+2 by AXIOMS:24; then A11: 1 <= j+1 & j+1 <= width GoB f by A7,AXIOMS:22,NAT_1:29; A12: i+1+1 = i+(1+1) by XCMPLX_1:1; then A13: i+1 < len GoB f by A6,NAT_1:38; j+1+1 = j+(1+1) by XCMPLX_1:1; then A14: j+1 < width GoB f by A7,NAT_1:38; A15: 1 <= i+1 by NAT_1:29; assume A16: LSeg(1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) c= Int cell(GoB f,i+1,j) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+1)) } by A7,A12,A13,A14,A15,GOBOARD6:67; then A17: L~f meets Int cell(GoB f,i+1,j) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)* (i+2,j+1)) } by A16,XBOOLE_1:63; A18: L~f misses Int cell(GoB f,i+1,j) by A10,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j+1) by A11,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i+1,j) \/ Int cell(GoB f,i+1,j+1) by A18,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+1)) } by A17,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A19: LSeg(f/.(k+1),(GoB f)*(i+2,j+1)) = LSeg(f,k0) by A6,A8,A11,A12,A15,GOBOARD7:42; A20: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A21: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A10,A13,A19,A20,A21,GOBOARD7:64; end; theorem for k st 1 <= k & k+2 <= len f for i st 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,1) & (f/.k = (GoB f)*(i+2,1) & f/.(k+2) = (GoB f)*(i+1,2) or f/.(k+2) = (GoB f)*(i+2,1) & f/.k = (GoB f)*(i+1,2)) holds LSeg(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|, 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i such that A6: 1 <= i & i+2 <= len GoB f and A7: f/.(k+1) = (GoB f)*(i+1,1) and A8: (f/.k = (GoB f)*(i+2,1) & f/.(k+2) = (GoB f)*(i+1,2) or f/.(k+2) = (GoB f)*(i+2,1) & f/.k = (GoB f)*(i+1,2)); width GoB f <> 0 by GOBOARD1:def 5; then A9: 0+1 <= width GoB f by RLVECT_1:99; i+1+1 = i+(1+1) by XCMPLX_1:1; then A10: i+1 < len GoB f by A6,NAT_1:38; A11: 1 < width GoB f by GOBOARD7:35; A12: 0 < width GoB f by A9,NAT_1:38; A13: i < len GoB f by A10,NAT_1:38; assume A14: LSeg(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|, 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,2))) meets L~f; LSeg(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|, 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1+1))) c= Int cell(GoB f,i,0) \/ Int cell(GoB f,i,1) \/ { 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1)) } by A6,A11,A13,GOBOARD6:69; then A15: L~f meets Int cell(GoB f,i,0) \/ Int cell(GoB f,i,1) \/ { 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1)) } by A14,XBOOLE_1:63; A16: L~f misses Int cell(GoB f,i,0) by A12,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i,1) by A9,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i,0) \/ Int cell(GoB f,i,1) by A16,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1)) } by A15,XBOOLE_1:70; then 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A17: LSeg(f/.(k+1),(GoB f)*(i,1)) = LSeg(f,k0) by A6,A7,A9,A10,GOBOARD7:42; A18: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A19: 1+1 = 2; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A10,A11,A17,A18,A19,A20,GOBOARD7:63; end; theorem for k st 1 <= k & k+2 <= len f for i st 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,1) & (f/.k = (GoB f)*(i,1) & f/.(k+2) = (GoB f)*(i+1,2) or f/.(k+2) = (GoB f)*(i,1) & f/.k = (GoB f)*(i+1,2)) holds LSeg(1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|, 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i such that A6: 1 <= i & i+2 <= len GoB f and A7: f/.(k+1) = (GoB f)*(i+1,1) and A8: (f/.k = (GoB f)*(i,1) & f/.(k+2) = (GoB f)*(i+1,2) or f/.(k+2) = (GoB f)*(i,1) & f/.k = (GoB f)*(i+1,2)); width GoB f <> 0 by GOBOARD1:def 5; then A9: 0+1 <= width GoB f by RLVECT_1:99; A10: i+1+1 = i+(1+1) by XCMPLX_1:1; then A11: i+1 < len GoB f by A6,NAT_1:38; A12: 1 < width GoB f by GOBOARD7:35; A13: 0 < width GoB f by A9,NAT_1:38; A14: 1 <= i+1 by NAT_1:29; assume A15: LSeg(1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|, 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,2))) meets L~f; LSeg(1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|, 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,2))) c= Int cell(GoB f,i+1,0) \/ Int cell(GoB f,i+1,1) \/ { 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1)) } by A10,A11,A12,A14,GOBOARD6:69; then A16: L~f meets Int cell(GoB f,i+1,0) \/ Int cell(GoB f,i+1,1) \/ { 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1)) } by A15,XBOOLE_1:63; A17: L~f misses Int cell(GoB f,i+1,0) by A11,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,1) by A9,A11,GOBOARD7:14; then L~f misses Int cell(GoB f,i+1,0) \/ Int cell(GoB f,i+1,1) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg(f/.(k+1),(GoB f)*(i+2,1)) = LSeg(f,k0) by A6,A7,A9,A10,A14,GOBOARD7:42; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; A21: 1+1 = 2; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A11,A12,A18,A19,A20,A21,GOBOARD7:63; end; theorem for k st 1 <= k & k+2 <= len f for i st 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,width GoB f) & (f/.k = (GoB f)*(i+2,width GoB f) & f/.(k+2) = (GoB f)*(i+1,width GoB f -' 1) or f/.(k+2) = (GoB f)*(i+2,width GoB f) & f/.k = (GoB f)*(i+1,width GoB f -' 1)) holds LSeg(1/2*((GoB f)*(i,width GoB f -' 1)+(GoB f)*(i+1,width GoB f)), 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]|) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i such that A6: 1 <= i & i+2 <= len GoB f and A7: f/.(k+1) = (GoB f)*(i+1,width GoB f) and A8: (f/.k = (GoB f)*(i+2,width GoB f) & f/.(k+2) = (GoB f)*(i+1,width GoB f -' 1) or f/.(k+2) = (GoB f)*(i+2,width GoB f) & f/.k = (GoB f)*(i+1,width GoB f -' 1)); A9: 1 < width GoB f by GOBOARD7:35; then A10: width GoB f -'1 +1 = width GoB f by AMI_5:4; then A11: 1 <= width GoB f -' 1 by A9,NAT_1:38; A12: width GoB f -' 1 < width GoB f by A10,NAT_1:38; i+1+1 = i+(1+1) by XCMPLX_1:1; then A13: i+1 < len GoB f by A6,NAT_1:38; then A14: i < len GoB f by NAT_1:38; assume A15: LSeg(1/2*((GoB f)*(i,width GoB f -' 1)+(GoB f)*(i+1,width GoB f)), 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]|) meets L~f; 1/2*((GoB f)*(i,width GoB f -' 1)+(GoB f)*(i+1,width GoB f)) = 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f -' 1)) by A6,A10,A11,A13,GOBOARD7:11; then LSeg(1/2*((GoB f)*(i,width GoB f -' 1)+(GoB f)*(i+1,width GoB f)), 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]|) c= Int cell(GoB f,i,width GoB f -' 1) \/ Int cell(GoB f,i,width GoB f) \/ { 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f)) } by A6,A9,A14,GOBOARD6:70; then A16: L~f meets Int cell(GoB f,i,width GoB f -' 1) \/ Int cell(GoB f,i,width GoB f) \/ { 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f)) } by A15,XBOOLE_1:63; A17: L~f misses Int cell(GoB f,i,width GoB f -' 1) by A12,A14,GOBOARD7:14; L~f misses Int cell(GoB f,i,width GoB f) by A14,GOBOARD7:14; then L~f misses Int cell(GoB f,i,width GoB f -' 1) \/ Int cell(GoB f,i,width GoB f) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i,width GoB f)+(GoB f)* (i+1,width GoB f)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg(f/.(k+1),(GoB f)*(i,width GoB f)) = LSeg(f,k0) by A6,A7,A9,A13,GOBOARD7:42; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A10,A11,A12,A13,A18,A19,A20,GOBOARD7:64; end; theorem for k st 1 <= k & k+2 <= len f for i st 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,width GoB f) & (f/.k = (GoB f)*(i,width GoB f) & f/.(k+2) = (GoB f)*(i+1,width GoB f -' 1) or f/.(k+2) = (GoB f)*(i,width GoB f) & f/.k = (GoB f)*(i+1,width GoB f -' 1)) holds LSeg(1/2*((GoB f)*(i+1,width GoB f -' 1)+(GoB f)*(i+2,width GoB f)), 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i such that A6: 1 <= i & i+2 <= len GoB f and A7: f/.(k+1) = (GoB f)*(i+1,width GoB f) and A8: (f/.k = (GoB f)*(i,width GoB f) & f/.(k+2) = (GoB f)*(i+1,width GoB f -' 1) or f/.(k+2) = (GoB f)*(i,width GoB f) & f/.k = (GoB f)*(i+1,width GoB f -' 1)); A9: 1 < width GoB f by GOBOARD7:35; A10: 1 <= width GoB f by GOBOARD7:35; then A11: width GoB f -'1 +1 = width GoB f by AMI_5:4; then A12: 1 <= width GoB f -' 1 by A9,NAT_1:38; A13: width GoB f -' 1 < width GoB f by A11,NAT_1:38; A14: i+1+1 = i+(1+1) by XCMPLX_1:1; then A15: i+1 < len GoB f by A6,NAT_1:38; A16: 1 <= i+1 by NAT_1:29; assume A17: LSeg(1/2*((GoB f)*(i+1,width GoB f -' 1)+(GoB f)*(i+2,width GoB f)), 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|) meets L~f; 1/2*((GoB f)*(i+1,width GoB f -' 1)+(GoB f)*(i+2,width GoB f)) = 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f -' 1)) by A6,A11,A12,A14,A16,GOBOARD7:11; then LSeg(1/2*((GoB f)*(i+1,width GoB f -' 1)+(GoB f)*(i+2,width GoB f)), 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|) c= Int cell(GoB f,i+1,width GoB f -' 1) \/ Int cell(GoB f,i+1,width GoB f) \/ { 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f)) } by A9,A14,A15,A16,GOBOARD6:70; then A18: L~f meets Int cell(GoB f,i+1,width GoB f -' 1) \/ Int cell(GoB f,i+1,width GoB f) \/ { 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f)) } by A17,XBOOLE_1:63; A19: L~f misses Int cell(GoB f,i+1,width GoB f -' 1) by A13,A15,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,width GoB f) by A15,GOBOARD7:14; then L~f misses Int cell(GoB f,i+1,width GoB f -' 1) \/ Int cell(GoB f,i+1,width GoB f) by A19,XBOOLE_1:70; then L~f meets {1/2*((GoB f)*(i+1,width GoB f)+(GoB f)* (i+2,width GoB f))} by A18,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A20: LSeg(f/.(k+1),(GoB f)*(i+2,width GoB f)) = LSeg(f,k0) by A6,A7,A10,A14,A16,GOBOARD7:42; A21: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A22: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A11,A12,A13,A15,A20,A21,A22,GOBOARD7:64; end; theorem for k st 1 <= k & k+2 <= len f for i,j st 1 <= j & j+1 <= width GoB f & 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i,j+1) & f/.(k+2) = (GoB f)*(i+2,j+1) or f/.(k+2) = (GoB f)*(i,j+1) & f/.k = (GoB f)*(i+2,j+1)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let i,j such that A6: 1 <= j & j+1 <= width GoB f and A7: 1 <= i & i+2 <= len GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i,j+1) & f/.(k+2) = (GoB f)*(i+2,j+1) or f/.(k+2) = (GoB f)*(i,j+1) & f/.k = (GoB f)*(i+2,j+1)); i < i+2 by REAL_1:69; then A10: i <= len GoB f by A7,AXIOMS:22; i+1 <= i+2 by AXIOMS:24; then A11: 1 <= i+1 & i+1 <= len GoB f by A7,AXIOMS:22,NAT_1:29; A12: i+1+1 = i+(1+1) by XCMPLX_1:1; then A13: i+1 < len GoB f by A7,NAT_1:38; A14: j < width GoB f by A6,NAT_1:38; assume A15: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1+1,j+1))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A6,A7,A12,A13,A14,GOBOARD6:68; then A16: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A12,A15,XBOOLE_1:63 ; A17: L~f misses Int cell(GoB f,i,j) by A10,A14,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j) by A11,A14,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg(f/.(k+1),(GoB f)*(i+1,j)) = LSeg(f,k0) by A6,A8,A11,GOBOARD7:41; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A13,A14,A18,A19,A20,GOBOARD7:64; end; theorem for k st 1 <= k & k+2 <= len f for j,i st 1 <= j & j+2 <= width GoB f & 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+1,j+2) & f/.(k+2) = (GoB f)*(i+2,j+1) or f/.(k+2) = (GoB f)*(i+1,j+2) & f/.k = (GoB f)*(i+2,j+1)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j,i such that A6: 1 <= j & j+2 <= width GoB f and A7: 1 <= i & i+2 <= len GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+1,j+2) & f/.(k+2) = (GoB f)*(i+2,j+1) or f/.(k+2) = (GoB f)*(i+1,j+2) & f/.k = (GoB f)*(i+2,j+1)); i < i+2 by REAL_1:69; then A10: i < len GoB f by A7,AXIOMS:22; i+1 <= i+2 by AXIOMS:24; then A11: 1 <= i+1 & i+1 <= len GoB f by A7,AXIOMS:22,NAT_1:29; j+1+1 = j+(1+1) by XCMPLX_1:1; then A12: j+1 < width GoB f by A6,NAT_1:38; A13: i+1+1 = i+(1+1) by XCMPLX_1:1; then A14: i+1 < len GoB f by A7,NAT_1:38; A15: j < width GoB f by A12,NAT_1:38; assume A16: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1+1,j+1))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A6,A7,A13,A14,A15,GOBOARD6:68; then A17: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A13,A16,XBOOLE_1:63 ; A18: L~f misses Int cell(GoB f,i,j) by A10,A15,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j) by A11,A15,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) by A18,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A17,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A19: LSeg( f/.(k+1),(GoB f)*(i+1,j)) = LSeg(f,k0) by A6,A8,A11,A12,GOBOARD7:41; A20: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A21: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A8,A9,A11,A12,A13,A14,A19,A20,A21,GOBOARD7:61; end; theorem for k st 1 <= k & k+2 <= len f for j,i st 1 <= j & j+2 <= width GoB f & 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+1,j+2) & f/.(k+2) = (GoB f)*(i,j+1) or f/.(k+2) = (GoB f)*(i+1,j+2) & f/.k = (GoB f)*(i,j+1)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j,i such that A6: 1 <= j & j+2 <= width GoB f and A7: 1 <= i & i+2 <= len GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+1,j+2) & f/.(k+2) = (GoB f)*(i,j+1) or f/.(k+2) = (GoB f)*(i+1,j+2) & f/.k = (GoB f)*(i,j+1)); i < i+2 by REAL_1:69; then A10: i < len GoB f by A7,AXIOMS:22; i+1 <= i+2 by AXIOMS:24; then A11: 1 <= i+1 & i+1 <= len GoB f by A7,AXIOMS:22,NAT_1:29; j+1+1 = j+(1+1) by XCMPLX_1:1; then A12: j+1 < width GoB f by A6,NAT_1:38; i+1+1 = i+(1+1) by XCMPLX_1:1; then A13: i+1 < len GoB f by A7,NAT_1:38; A14: j < width GoB f by A12,NAT_1:38; assume A15: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A6,A7,A13,A14,GOBOARD6:68; then A16: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A15,XBOOLE_1:63; A17: L~f misses Int cell(GoB f,i,j) by A10,A14,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j) by A11,A14,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg( f/.(k+1),(GoB f)*(i+1,j)) = LSeg(f,k0) by A6,A8,A11,A12,GOBOARD7:41; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A10,A12,A18,A19,A20,GOBOARD7:62; end; theorem for k st 1 <= k & k+2 <= len f for j,i st 1 <= j & j+1 <= width GoB f & 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,j) & (f/.k = (GoB f)*(i,j) & f/.(k+2) = (GoB f)*(i+2,j) or f/.(k+2) = (GoB f)*(i,j) & f/.k = (GoB f)*(i+2,j)) holds LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j,i such that A6: 1 <= j & j+1 <= width GoB f and A7: 1 <= i & i+2 <= len GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j) and A9: (f/.k = (GoB f)*(i,j) & f/.(k+2) = (GoB f)*(i+2,j) or f/.(k+2) = (GoB f)*(i,j) & f/.k = (GoB f)*(i+2,j)); i < i+2 by REAL_1:69; then A10: i <= len GoB f by A7,AXIOMS:22; i+1 <= i+2 by AXIOMS:24; then A11: 1 <= i+1 & i+1 <= len GoB f by A7,AXIOMS:22,NAT_1:29; i+1+1 = i+(1+1) by XCMPLX_1:1; then A12: i+1 < len GoB f by A7,NAT_1:38; A13: j < width GoB f by A6,NAT_1:38; assume A14: LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) meets L~f; LSeg(1/2*((GoB f)*(i,j)+(GoB f)*(i+1,j+1)), 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+2,j+1))) c= Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A6,A7,A12,A13,GOBOARD6:68; then A15: L~f meets Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) \/ { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A14,XBOOLE_1:63; A16: L~f misses Int cell(GoB f,i,j) by A10,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j) by A11,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j) \/ Int cell(GoB f,i+1,j) by A16,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) } by A15,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j)+(GoB f)*(i+1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A17: LSeg(f/.(k+1),(GoB f)*(i+1,j+1)) = LSeg(f,k0) by A6,A8,A11,GOBOARD7:41; A18: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A19: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A12,A13,A17,A18,A19,GOBOARD7:63; end; theorem for k st 1 <= k & k+2 <= len f for j,i st 1 <= j & j+2 <= width GoB f & 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+1,j) & f/.(k+2) = (GoB f)*(i+2,j+1) or f/.(k+2) = (GoB f)*(i+1,j) & f/.k = (GoB f)*(i+2,j+1)) holds LSeg(1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j,i such that A6: 1 <= j & j+2 <= width GoB f and A7: 1 <= i & i+2 <= len GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+1,j) & f/.(k+2) = (GoB f)*(i+2,j+1) or f/.(k+2) = (GoB f)*(i+1,j) & f/.k = (GoB f)*(i+2,j+1)); i < i+2 by REAL_1:69; then A10: i < len GoB f by A7,AXIOMS:22; i+1 <= i+2 by AXIOMS:24; then A11: 1 <= i+1 & i+1 <= len GoB f by A7,AXIOMS:22,NAT_1:29; A12: j+1+1 = j+(1+1) by XCMPLX_1:1; then A13: j+1 < width GoB f by A6,NAT_1:38; A14: i+1+1 = i+(1+1) by XCMPLX_1:1; then A15: i+1 < len GoB f by A7,NAT_1:38; A16: 1 <= j+1 by NAT_1:29; assume A17: LSeg(1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) c= Int cell(GoB f,i,j+1) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+1,j+2)) } by A7,A12,A13,A15,A16,GOBOARD6:68; then A18: L~f meets Int cell(GoB f,i,j+1) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)* (i+1,j+2)) } by A17,XBOOLE_1:63; A19: L~f misses Int cell(GoB f,i,j+1) by A10,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j+1) by A11,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j+1) \/ Int cell(GoB f,i+1,j+1) by A19,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+1,j+2)) } by A18,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+1,j+2)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A20: LSeg(f/.(k+1),(GoB f)*(i+1,j+2)) = LSeg(f,k0) by A6,A8,A11,A12,A16,GOBOARD7:41; A21: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A22: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A8,A9,A11,A13,A14,A15,A20,A21,A22,GOBOARD7:61; end; theorem for k st 1 <= k & k+2 <= len f for j,i st 1 <= j & j+2 <= width GoB f & 1 <= i & i+2 <= len GoB f & f/.(k+1) = (GoB f)*(i+1,j+1) & (f/.k = (GoB f)*(i+1,j) & f/.(k+2) = (GoB f)*(i,j+1) or f/.(k+2) = (GoB f)*(i+1,j) & f/.k = (GoB f)*(i,j+1)) holds LSeg(1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j,i such that A6: 1 <= j & j+2 <= width GoB f and A7: 1 <= i & i+2 <= len GoB f and A8: f/.(k+1) = (GoB f)*(i+1,j+1) and A9: (f/.k = (GoB f)*(i+1,j) & f/.(k+2) = (GoB f)*(i,j+1) or f/.(k+2) = (GoB f)*(i+1,j) & f/.k = (GoB f)*(i,j+1)); i < i+2 by REAL_1:69; then A10: i < len GoB f by A7,AXIOMS:22; i+1 <= i+2 by AXIOMS:24; then A11: 1 <= i+1 & i+1 <= len GoB f by A7,AXIOMS:22,NAT_1:29; A12: j+1+1 = j+(1+1) by XCMPLX_1:1; then A13: j+1 < width GoB f by A6,NAT_1:38; i+1+1 = i+(1+1) by XCMPLX_1:1; then A14: i+1 < len GoB f by A7,NAT_1:38; A15: 1 <= j+1 by NAT_1:29; assume A16: LSeg(1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) meets L~f; LSeg(1/2*((GoB f)*(i,j+1)+(GoB f)*(i+1,j+2)), 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+2,j+2))) c= Int cell(GoB f,i,j+1) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+1,j+2)) } by A7,A12,A13,A14,A15,GOBOARD6:68; then A17: L~f meets Int cell(GoB f,i,j+1) \/ Int cell(GoB f,i+1,j+1) \/ { 1/2*((GoB f)*(i+1,j+1)+(GoB f)* (i+1,j+2)) } by A16,XBOOLE_1:63; A18: L~f misses Int cell(GoB f,i,j+1) by A10,A13,GOBOARD7:14; L~f misses Int cell(GoB f,i+1,j+1) by A11,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,i,j+1) \/ Int cell(GoB f,i+1,j+1) by A18,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+1,j+2)) } by A17,XBOOLE_1:70; then 1/2*((GoB f)*(i+1,j+1)+(GoB f)*(i+1,j+2)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A19: LSeg(f/.(k+1),(GoB f)*(i+1,j+2)) = LSeg(f,k0) by A6,A8,A11,A12,A15,GOBOARD7:41; A20: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A21: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A9,A10,A13,A19,A20,A21,GOBOARD7:62; end; theorem for k st 1 <= k & k+2 <= len f for j st 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(1,j+1) & (f/.k = (GoB f)*(1,j+2) & f/.(k+2) = (GoB f)*(2,j+1) or f/.(k+2) = (GoB f)*(1,j+2) & f/.k = (GoB f)*(2,j+1)) holds LSeg(1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|, 1/2*((GoB f)*(1,j)+(GoB f)*(2,j+1))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j such that A6: 1 <= j & j+2 <= width GoB f and A7: f/.(k+1) = (GoB f)*(1,j+1) and A8: (f/.k = (GoB f)*(1,j+2) & f/.(k+2) = (GoB f)*(2,j+1) or f/.(k+2) = (GoB f)*(1,j+2) & f/.k = (GoB f)*(2,j+1)); len GoB f <> 0 by GOBOARD1:def 5; then A9: 0+1 <= len GoB f by RLVECT_1:99; j+1+1 = j+(1+1) by XCMPLX_1:1; then A10: j+1 < width GoB f by A6,NAT_1:38; A11: 1 < len GoB f by GOBOARD7:34; A12: 0 < len GoB f by A9,NAT_1:38; A13: j < width GoB f by A10,NAT_1:38; assume A14: LSeg(1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|, 1/2*((GoB f)*(1,j)+(GoB f)*(2,j+1))) meets L~f; LSeg(1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|, 1/2*((GoB f)*(1,j)+(GoB f)*(1+1,j+1))) c= Int cell(GoB f,0,j) \/ Int cell(GoB f,1,j) \/ { 1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1)) } by A6,A11,A13,GOBOARD6:71; then A15: L~f meets Int cell(GoB f,0,j) \/ Int cell(GoB f,1,j) \/ { 1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1)) } by A14,XBOOLE_1:63; A16: L~f misses Int cell(GoB f,0,j) by A12,A13,GOBOARD7:14; L~f misses Int cell(GoB f,1,j) by A9,A13,GOBOARD7:14; then L~f misses Int cell(GoB f,0,j) \/ Int cell(GoB f,1,j) by A16,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1)) } by A15,XBOOLE_1:70; then 1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A17: LSeg(f/.(k+1),(GoB f)*(1,j)) = LSeg(f,k0) by A6,A7,A9,A10,GOBOARD7:41; A18: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A19: 1+1 = 2; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A10,A11,A17,A18,A19,A20,GOBOARD7:61; end; theorem for k st 1 <= k & k+2 <= len f for j st 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(1,j+1) & (f/.k = (GoB f)*(1,j) & f/.(k+2) = (GoB f)*(2,j+1) or f/.(k+2) = (GoB f)*(1,j) & f/.k = (GoB f)*(2,j+1)) holds LSeg(1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|, 1/2*((GoB f)*(1,j+1)+(GoB f)*(2,j+2))) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j such that A6: 1 <= j & j+2 <= width GoB f and A7: f/.(k+1) = (GoB f)*(1,j+1) and A8: (f/.k = (GoB f)*(1,j) & f/.(k+2) = (GoB f)*(2,j+1) or f/.(k+2) = (GoB f)*(1,j) & f/.k = (GoB f)*(2,j+1)); len GoB f <> 0 by GOBOARD1:def 5; then A9: 0+1 <= len GoB f by RLVECT_1:99; A10: j+1+1 = j+(1+1) by XCMPLX_1:1; then A11: j+1 < width GoB f by A6,NAT_1:38; A12: 1 < len GoB f by GOBOARD7:34; A13: 0 < len GoB f by A9,NAT_1:38; A14: 1 <= j+1 by NAT_1:29; assume A15: LSeg(1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|, 1/2*((GoB f)*(1,j+1)+(GoB f)*(2,j+2))) meets L~f; LSeg(1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|, 1/2*((GoB f)*(1,j+1)+(GoB f)*(2,j+2))) c= Int cell(GoB f,0,j+1) \/ Int cell(GoB f,1,j+1) \/ { 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2)) } by A10,A11,A12,A14,GOBOARD6:71; then A16: L~f meets Int cell(GoB f,0,j+1) \/ Int cell(GoB f,1,j+1) \/ { 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2)) } by A15,XBOOLE_1:63; A17: L~f misses Int cell(GoB f,0,j+1) by A11,A13,GOBOARD7:14; L~f misses Int cell(GoB f,1,j+1) by A9,A11,GOBOARD7:14; then L~f misses Int cell(GoB f,0,j+1) \/ Int cell(GoB f,1,j+1) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg(f/.(k+1),(GoB f)*(1,j+2)) = LSeg(f,k0) by A6,A7,A9,A10,A14,GOBOARD7:41; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; A21: 1+1 = 2; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A11,A12,A18,A19,A20,A21,GOBOARD7:61; end; theorem for k st 1 <= k & k+2 <= len f for j st 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(len GoB f,j+1) & (f/.k = (GoB f)*(len GoB f,j+2) & f/.(k+2) = (GoB f)*(len GoB f -' 1,j+1) or f/.(k+2) = (GoB f)*(len GoB f,j+2) & f/.k = (GoB f)*(len GoB f -' 1,j+1)) holds LSeg(1/2*((GoB f)*(len GoB f -' 1,j)+(GoB f)*(len GoB f,j+1)), 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j such that A6: 1 <= j & j+2 <= width GoB f and A7: f/.(k+1) = (GoB f)*(len GoB f,j+1) and A8: (f/.k = (GoB f)*(len GoB f,j+2) & f/.(k+2) = (GoB f)*(len GoB f -' 1,j+1) or f/.(k+2) = (GoB f)*(len GoB f,j+2) & f/.k = (GoB f)*(len GoB f -' 1,j+1)); A9: 1 < len GoB f by GOBOARD7:34; then A10: len GoB f -'1 +1 = len GoB f by AMI_5:4; then A11: 1 <= len GoB f -' 1 by A9,NAT_1:38; A12: len GoB f -' 1 < len GoB f by A10,NAT_1:38; j+1+1 = j+(1+1) by XCMPLX_1:1; then A13: j+1 < width GoB f by A6,NAT_1:38; then A14: j < width GoB f by NAT_1:38; assume A15: LSeg(1/2*((GoB f)*(len GoB f -' 1,j)+(GoB f)*(len GoB f,j+1)), 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|) meets L~f; 1/2*((GoB f)*(len GoB f -' 1,j)+(GoB f)*(len GoB f,j+1)) = 1/2*((GoB f)*(len GoB f -' 1,j+1)+(GoB f)*(len GoB f,j)) by A6,A10,A11,A13,GOBOARD7:11; then LSeg(1/2*((GoB f)*(len GoB f -' 1,j)+(GoB f)*(len GoB f,j+1)), 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|) c= Int cell(GoB f,len GoB f -' 1,j) \/ Int cell(GoB f,len GoB f,j) \/ { 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1)) } by A6,A9,A14,GOBOARD6:72; then A16: L~f meets Int cell(GoB f,len GoB f -' 1,j) \/ Int cell(GoB f,len GoB f,j) \/ { 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1)) } by A15,XBOOLE_1:63; A17: L~f misses Int cell(GoB f,len GoB f -' 1,j) by A12,A14,GOBOARD7:14; L~f misses Int cell(GoB f,len GoB f,j) by A14,GOBOARD7:14; then L~f misses Int cell(GoB f,len GoB f -' 1,j) \/ Int cell(GoB f,len GoB f,j) by A17,XBOOLE_1:70; then L~f meets { 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1)) } by A16,XBOOLE_1:70; then 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A18: LSeg(f/.(k+1),(GoB f)*(len GoB f,j)) = LSeg(f,k0) by A6,A7,A9,A13,GOBOARD7:41; A19: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A20: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A10,A11,A12,A13,A18,A19,A20,GOBOARD7:62; end; theorem for k st 1 <= k & k+2 <= len f for j st 1 <= j & j+2 <= width GoB f & f/.(k+1) = (GoB f)*(len GoB f,j+1) & (f/.k = (GoB f)*(len GoB f,j) & f/.(k+2) = (GoB f)*(len GoB f -' 1,j+1) or f/.(k+2) = (GoB f)*(len GoB f,j) & f/.k = (GoB f)*(len GoB f -' 1,j+1)) holds LSeg(1/2*((GoB f)*(len GoB f -' 1,j+1)+(GoB f)*(len GoB f,j+2)), 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|) misses L~f proof let k such that A1: k >= 1 and A2: k+2 <= len f; A3: 1 <= k+1 by NAT_1:29; A4: k+1+1 = k+(1+1) by XCMPLX_1:1; then A5: k+1 < len f by A2,NAT_1:38; let j such that A6: 1 <= j & j+2 <= width GoB f and A7: f/.(k+1) = (GoB f)*(len GoB f,j+1) and A8: (f/.k = (GoB f)*(len GoB f,j) & f/.(k+2) = (GoB f)*(len GoB f -' 1,j+1) or f/.(k+2) = (GoB f)*(len GoB f,j) & f/.k = (GoB f)*(len GoB f -' 1,j+1)); A9: 1 < len GoB f by GOBOARD7:34; A10: 1 <= len GoB f by GOBOARD7:34; then A11: len GoB f -'1 +1 = len GoB f by AMI_5:4; then A12: 1 <= len GoB f -' 1 by A9,NAT_1:38; A13: len GoB f -' 1 < len GoB f by A11,NAT_1:38; A14: j+1+1 = j+(1+1) by XCMPLX_1:1; then A15: j+1 < width GoB f by A6,NAT_1:38; A16: 1 <= j+1 by NAT_1:29; assume A17: LSeg(1/2*((GoB f)*(len GoB f -' 1,j+1)+(GoB f)*(len GoB f,j+2)), 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|) meets L~f; 1/2*((GoB f)*(len GoB f -' 1,j+1)+(GoB f)*(len GoB f,j+2)) = 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f -' 1,j+2)) by A6,A11,A12,A14,A16,GOBOARD7:11; then LSeg(1/2*((GoB f)*(len GoB f -' 1,j+1)+(GoB f)*(len GoB f,j+2)), 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|) c= Int cell(GoB f,len GoB f -' 1,j+1) \/ Int cell(GoB f,len GoB f,j+1) \/ { 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2)) } by A9,A14,A15,A16,GOBOARD6:72; then A18: L~f meets Int cell(GoB f,len GoB f -' 1,j+1) \/ Int cell(GoB f,len GoB f,j+1) \/ { 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2)) } by A17,XBOOLE_1:63; A19: L~f misses Int cell(GoB f,len GoB f -' 1,j+1) by A13,A15,GOBOARD7:14; L~f misses Int cell(GoB f,len GoB f,j+1) by A15,GOBOARD7:14; then L~f misses Int cell(GoB f,len GoB f -' 1,j+1) \/ Int cell(GoB f,len GoB f,j+1) by A19,XBOOLE_1:70; then L~f meets {1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))} by A18,XBOOLE_1:70; then 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2)) in L~f by ZFMISC_1:56; then consider k0 being Nat such that 1 <= k0 & k0+1 <= len f and A20: LSeg(f/.(k+1),(GoB f)*(len GoB f,j+2)) = LSeg(f,k0) by A6,A7,A10,A14,A16,GOBOARD7:41; A21: LSeg(f,k0) c= L~f & LSeg(f,k) c= L~f & LSeg(f,k+1) c= L~f by TOPREAL3:26; A22: LSeg(f,k) = LSeg(f/.k,f/.(k+1)) by A1,A5,TOPREAL1:def 5; LSeg(f,k+1) = LSeg(f/.(k+1),f/.(k+2)) by A2,A3,A4,TOPREAL1:def 5; hence contradiction by A6,A7,A8,A11,A12,A13,A15,A20,A21,A22,GOBOARD7:62; end; reserve P for Subset of TOP-REAL 2; theorem Th21: (for p st p in P holds p`1 < (GoB f)*(1,1)`1) implies P misses L~f proof assume A1: for p st p in P holds p`1 < (GoB f)*(1,1)`1; A2: f is_sequence_on GoB f by GOBOARD5:def 5; assume P meets L~f; then consider x such that A3: x in P and A4: x in L~f by XBOOLE_0:3; reconsider x as Point of TOP-REAL 2 by A3; A5: x`1 < (GoB f)*(1,1)`1 by A1,A3; consider i such that A6: 1 <= i and A7: i+1 <= len f and A8: x in LSeg(f/.i,f/.(i+1)) by A4,SPPOL_2:14; A9: 1 < width GoB f by GOBOARD7:35; per cases; suppose (f/.i)`1 <= (f/.(i+1))`1; then A10: (f/.i)`1 <= x `1 by A8,TOPREAL1:9; i <= len f by A7,NAT_1:38; then i in dom f by A6,FINSEQ_3:27; then consider i1,j1 such that A11: [i1,j1] in Indices GoB f and A12: f/.i = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A13: 1 <= j1 & j1 <= width GoB f & 1 <= i1 & i1 <= len GoB f by A11,GOBOARD5:1; then A14: (f/.i)`1 = (GoB f)*(i1,1)`1 by A12,GOBOARD5:3; then 1 < i1 by A5,A10,A13,AXIOMS:21; then (GoB f)*(1,1)`1 < (f/.i)`1 by A9,A13,A14,GOBOARD5:4; hence contradiction by A5,A10,AXIOMS:22; suppose (f/.i)`1 >= (f/.(i+1))`1; then A15: (f/.(i+1))`1 <= x `1 by A8,TOPREAL1:9; 1 <= i+1 by NAT_1:29; then i+1 in dom f by A7,FINSEQ_3:27; then consider i1,j1 such that A16: [i1,j1] in Indices GoB f and A17: f/.(i+1) = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A18: 1 <= j1 & j1 <= width GoB f & 1 <= i1 & i1 <= len GoB f by A16,GOBOARD5:1; then A19: (f/.(i+1))`1 = (GoB f)*(i1,1)`1 by A17,GOBOARD5:3; then 1 < i1 by A5,A15,A18,AXIOMS:21; then (GoB f)*(1,1)`1 < (f/.(i+1))`1 by A9,A18,A19,GOBOARD5:4; hence contradiction by A5,A15,AXIOMS:22; end; theorem Th22: (for p st p in P holds p`1 > (GoB f)*(len GoB f,1)`1) implies P misses L~f proof assume A1: for p st p in P holds p`1 > (GoB f)*(len GoB f,1)`1; A2: f is_sequence_on GoB f by GOBOARD5:def 5; assume P meets L~f; then consider x such that A3: x in P and A4: x in L~f by XBOOLE_0:3; reconsider x as Point of TOP-REAL 2 by A3; A5: x`1 > (GoB f)*(len GoB f,1)`1 by A1,A3; consider i such that A6: 1 <= i and A7: i+1 <= len f and A8: x in LSeg(f/.i,f/.(i+1)) by A4,SPPOL_2:14; A9: 1 < width GoB f by GOBOARD7:35; per cases; suppose (f/.i)`1 >= (f/.(i+1))`1; then A10: (f/.i)`1 >= x `1 by A8,TOPREAL1:9; i <= len f by A7,NAT_1:38; then i in dom f by A6,FINSEQ_3:27; then consider i1,j1 such that A11: [i1,j1] in Indices GoB f and A12: f/.i = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A13: 1 <= j1 & j1 <= width GoB f & 1 <= i1 & i1 <= len GoB f by A11,GOBOARD5:1; then A14: (f/.i)`1 = (GoB f)*(i1,1)`1 by A12,GOBOARD5:3; then i1 < len GoB f by A5,A10,A13,AXIOMS:21; then (GoB f)*(len GoB f,1)`1 > (f/.i)`1 by A9,A13,A14,GOBOARD5:4; hence contradiction by A5,A10,AXIOMS:22; suppose (f/.i)`1 <= (f/.(i+1))`1; then A15: (f/.(i+1))`1 >= x `1 by A8,TOPREAL1:9; 1 <= i+1 by NAT_1:29; then i+1 in dom f by A7,FINSEQ_3:27; then consider i1,j1 such that A16: [i1,j1] in Indices GoB f and A17: f/.(i+1) = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A18: 1 <= j1 & j1 <= width GoB f & 1 <= i1 & i1 <= len GoB f by A16,GOBOARD5:1; then A19: (f/.(i+1))`1 = (GoB f)*(i1,1)`1 by A17,GOBOARD5:3; then i1 < len GoB f by A5,A15,A18,AXIOMS:21; then (GoB f)*(len GoB f,1)`1 > (f/.(i+1))`1 by A9,A18,A19,GOBOARD5:4; hence contradiction by A5,A15,AXIOMS:22; end; theorem Th23: (for p st p in P holds p`2 < (GoB f)*(1,1)`2) implies P misses L~f proof assume A1: for p st p in P holds p`2 < (GoB f)*(1,1)`2; A2: f is_sequence_on GoB f by GOBOARD5:def 5; assume P meets L~f; then consider x such that A3: x in P and A4: x in L~f by XBOOLE_0:3; reconsider x as Point of TOP-REAL 2 by A3; A5: x`2 < (GoB f)*(1,1)`2 by A1,A3; consider j such that A6: 1 <= j and A7: j+1 <= len f and A8: x in LSeg(f/.j,f/.(j+1)) by A4,SPPOL_2:14; A9: 1 < len GoB f by GOBOARD7:34; per cases; suppose (f/.j)`2 <= (f/.(j+1))`2; then A10: (f/.j)`2 <= x `2 by A8,TOPREAL1:10; j <= len f by A7,NAT_1:38; then j in dom f by A6,FINSEQ_3:27; then consider i1,j1 such that A11: [i1,j1] in Indices GoB f and A12: f/.j = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A13: 1 <= i1 & i1 <= len GoB f & 1 <= j1 & j1 <= width GoB f by A11,GOBOARD5:1; then A14: (f/.j)`2 = (GoB f)*(1,j1)`2 by A12,GOBOARD5:2; then 1 < j1 by A5,A10,A13,AXIOMS:21; then (GoB f)*(1,1)`2 < (f/.j)`2 by A9,A13,A14,GOBOARD5:5; hence contradiction by A5,A10,AXIOMS:22; suppose (f/.j)`2 >= (f/.(j+1))`2; then A15: (f/.(j+1))`2 <= x `2 by A8,TOPREAL1:10; 1 <= j+1 by NAT_1:29; then j+1 in dom f by A7,FINSEQ_3:27; then consider i1,j1 such that A16: [i1,j1] in Indices GoB f and A17: f/.(j+1) = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A18: 1 <= i1 & i1 <= len GoB f & 1 <= j1 & j1 <= width GoB f by A16,GOBOARD5:1; then A19: (f/.(j+1))`2 = (GoB f)*(1,j1)`2 by A17,GOBOARD5:2; then 1 < j1 by A5,A15,A18,AXIOMS:21; then (GoB f)*(1,1)`2 < (f/.(j+1))`2 by A9,A18,A19,GOBOARD5:5; hence contradiction by A5,A15,AXIOMS:22; end; theorem Th24: (for p st p in P holds p`2 > (GoB f)*(1,width GoB f)`2) implies P misses L~f proof assume A1: for p st p in P holds p`2 > (GoB f)*(1,width GoB f)`2; A2: f is_sequence_on GoB f by GOBOARD5:def 5; assume P meets L~f; then consider x such that A3: x in P and A4: x in L~f by XBOOLE_0:3; reconsider x as Point of TOP-REAL 2 by A3; A5: x`2 > (GoB f)*(1,width GoB f)`2 by A1,A3; consider j such that A6: 1 <= j and A7: j+1 <= len f and A8: x in LSeg(f/.j,f/.(j+1)) by A4,SPPOL_2:14; A9: 1 < len GoB f by GOBOARD7:34; per cases; suppose (f/.j)`2 >= (f/.(j+1))`2; then A10: (f/.j)`2 >= x `2 by A8,TOPREAL1:10; j <= len f by A7,NAT_1:38; then j in dom f by A6,FINSEQ_3:27; then consider i1,j1 such that A11: [i1,j1] in Indices GoB f and A12: f/.j = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A13: 1 <= i1 & i1 <= len GoB f & 1 <= j1 & j1 <= width GoB f by A11,GOBOARD5:1; then A14: (f/.j)`2 = (GoB f)*(1,j1)`2 by A12,GOBOARD5:2; then j1 < width GoB f by A5,A10,A13,AXIOMS:21; then (GoB f)*(1,width GoB f)`2 > (f/.j)`2 by A9,A13,A14,GOBOARD5:5; hence contradiction by A5,A10,AXIOMS:22; suppose (f/.j)`2 <= (f/.(j+1))`2; then A15: (f/.(j+1))`2 >= x `2 by A8,TOPREAL1:10; 1 <= j+1 by NAT_1:29; then j+1 in dom f by A7,FINSEQ_3:27; then consider i1,j1 such that A16: [i1,j1] in Indices GoB f and A17: f/.(j+1) = (GoB f)*(i1,j1) by A2,GOBOARD1:def 11; A18: 1 <= i1 & i1 <= len GoB f & 1 <= j1 & j1 <= width GoB f by A16,GOBOARD5:1; then A19: (f/.(j+1))`2 = (GoB f)*(1,j1)`2 by A17,GOBOARD5:2; then j1 < width GoB f by A5,A15,A18,AXIOMS:21; then (GoB f)*(1,width GoB f)`2 > (f/.(j+1))`2 by A9,A18,A19,GOBOARD5:5; hence contradiction by A5,A15,AXIOMS:22; end; theorem for i st 1 <= i & i+2 <= len GoB f holds LSeg(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|, 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|) misses L~f proof let i such that A1: 1 <= i & i+2 <= len GoB f; A2: 1 <= width GoB f by GOBOARD7:35; now let p such that A3: p in LSeg(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|, 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|); A4: i <= i+2 by NAT_1:29; then i <= len GoB f by A1,AXIOMS:22; then A5: (GoB f)*(i,1)`2 = (GoB f)*(1,1)`2 by A1,A2,GOBOARD5:2; i+1 <= i+2 by AXIOMS:24; then 1 <= i+1 & i+1 <= len GoB f by A1,AXIOMS:22,NAT_1:29; then A6: (GoB f)*(i+1,1)`2 = (GoB f)*(1,1)`2 by A2,GOBOARD5:2; 1 <= i+2 by A1,A4,AXIOMS:22; then A7: (GoB f)*(i+2,1)`2 = (GoB f)*(1,1)`2 by A1,A2,GOBOARD5:2; (1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|)`2 = (1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1)))`2- |[0,1]|`2 by TOPREAL3:8 .= 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))`2- |[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)- |[0,1]|`2 by A5,A6,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`2)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`2-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`2-1; then A8: 1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]| = |[(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|)`1, ((GoB f)*(1,1))`2-1]| by EUCLID:57; (1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|)`2 = (1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1)))`2- |[0,1]|`2 by TOPREAL3:8 .= 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))`2- |[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)- |[0,1]|`2 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`2)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`2-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`2-1; then 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]| = |[(1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|)`1, (GoB f)*(1,1)`2-1]| by EUCLID:57; then p`2 = (GoB f)*(1,1)`2 - 1 by A3,A8,TOPREAL3:18; hence p`2 < (GoB f)*(1,1)`2 by REAL_2:174; end; hence LSeg(1/2*((GoB f)*(i,1)+(GoB f)*(i+1,1))- |[0,1]|, 1/2*((GoB f)*(i+1,1)+(GoB f)*(i+2,1))- |[0,1]|) misses L~f by Th23; end; theorem LSeg((GoB f)*(1,1)- |[1,1]|,1/2*((GoB f)*(1,1)+(GoB f)*(2,1))- |[0,1]|) misses L~f proof A1: 1 <= width GoB f by GOBOARD7:35; now let p such that A2: p in LSeg((GoB f)*(1,1)- |[1,1]|, 1/2*((GoB f)*(1,1)+(GoB f)*(2,1))- |[0,1]|); 1 < len GoB f by GOBOARD7:34; then 1+1 <= len GoB f by NAT_1:38; then A3: (GoB f)*(2,1)`2 = (GoB f)*(1,1)`2 by A1,GOBOARD5:2; ((GoB f)*(1,1)- |[1,1]|)`2 = ((GoB f)*(1,1))`2- |[1,1]|`2 by TOPREAL3:8 .= (GoB f)*(1,1)`2-1 by EUCLID:56; then A4: (GoB f)*(1,1)- |[1,1]| = |[((GoB f)*(1,1)- |[1,1]|)`1,(GoB f)*(1,1)`2-1]| by EUCLID:57; (1/2*((GoB f)*(1,1)+(GoB f)*(2,1))- |[0,1]|)`2 = (1/2*((GoB f)*(1,1)+(GoB f)*(2,1)))`2- |[0,1]|`2 by TOPREAL3:8 .= 1/2*((GoB f)*(1,1)+(GoB f)*(2,1))`2- |[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)- |[0,1]|`2 by A3,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`2)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`2-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`2-1; then 1/2*((GoB f)*(1,1)+(GoB f)*(2,1))- |[0,1]| = |[(1/2*((GoB f)*(1,1)+(GoB f)*(2,1))- |[0,1]|)`1, (GoB f)*(1,1)`2-1]| by EUCLID:57; then p`2 = (GoB f)*(1,1)`2 - 1 by A2,A4,TOPREAL3:18; hence p`2 < (GoB f)*(1,1)`2 by REAL_2:174; end; hence LSeg((GoB f)*(1,1)- |[1,1]|, 1/2*((GoB f)*(1,1)+(GoB f)*(2,1))- |[0,1]|) misses L~f by Th23; end; theorem LSeg(1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))- |[0,1]|, (GoB f)*(len GoB f,1)+|[1,-1]|) misses L~f proof A1: 1 <= width GoB f by GOBOARD7:35; now let p such that A2: p in LSeg(1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))- |[0,1]|, (GoB f)*(len GoB f,1)+|[1,-1]|); A3: 1 < len GoB f by GOBOARD7:34; then A4: len GoB f -' 1 +1 = len GoB f by AMI_5:4; then A5: 1 <= len GoB f -' 1 by A3,NAT_1:38; len GoB f -' 1 <= len GoB f by A4,NAT_1:29; then A6: (GoB f)*(len GoB f -' 1,1)`2 = (GoB f)*(1,1)`2 by A1,A5,GOBOARD5:2; A7: (GoB f)*(len GoB f,1)`2 = (GoB f)*(1,1)`2 by A1,A3,GOBOARD5:2; (1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))- |[0,1]|)`2 = (1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1)))`2- |[0,1]|`2 by TOPREAL3:8 .= 1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))`2- |[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)- |[0,1]|`2 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`2+(GoB f)*(1,1)`2)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`2)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`2-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`2-1; then A8: 1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))- |[0,1]| = |[(1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))- |[0,1]|)`1, (GoB f)*(1,1)`2-1]| by EUCLID:57; ((GoB f)*(len GoB f,1)+|[1,-1]|)`2 = (GoB f)*(1,1)`2+|[1,-1]|`2 by A7,TOPREAL3:7 .= (GoB f)*(1,1)`2+-1 by EUCLID:56 .= (GoB f)*(1,1)`2-1 by XCMPLX_0:def 8; then (GoB f)*(len GoB f,1)+|[1,-1]| = |[((GoB f)*(len GoB f,1)+|[1,-1]|)`1,(GoB f)* (1,1)`2-1]| by EUCLID:57; then p`2 = (GoB f)*(1,1)`2 - 1 by A2,A8,TOPREAL3:18; hence p`2 < (GoB f)*(1,1)`2 by REAL_2:174; end; hence LSeg(1/2*((GoB f)*(len GoB f -' 1,1)+(GoB f)*(len GoB f,1))- |[0,1]|, (GoB f)*(len GoB f,1)+|[1,-1]|) misses L~f by Th23; end; theorem for i st 1 <= i & i+2 <= len GoB f holds LSeg(1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]|, 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|) misses L~f proof let i such that A1: 1 <= i & i+2 <= len GoB f; A2: 1 <= width GoB f by GOBOARD7:35; now let p such that A3: p in LSeg(1/2*((GoB f)*(i,width GoB f)+(GoB f)* (i+1,width GoB f))+|[0,1]|, 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|); A4: i <= i+2 by NAT_1:29; then i <= len GoB f by A1,AXIOMS:22; then A5: (GoB f)*(i,width GoB f)`2 = (GoB f)* (1,width GoB f)`2 by A1,A2,GOBOARD5:2; i+1 <= i+2 by AXIOMS:24; then 1 <= i+1 & i+1 <= len GoB f by A1,AXIOMS:22,NAT_1:29; then A6: (GoB f)*(i+1,width GoB f)`2 = (GoB f)* (1,width GoB f)`2 by A2,GOBOARD5:2; 1 <= i+2 by A1,A4,AXIOMS:22; then A7: (GoB f)*(i+2,width GoB f)`2 = (GoB f)*(1,width GoB f)`2 by A1,A2,GOBOARD5:2; (1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]|)`2 = (1/2*((GoB f)*(i,width GoB f)+(GoB f)* (i+1,width GoB f)))`2+|[0,1]|`2 by TOPREAL3:7 .= 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))`2+|[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+|[0,1]|`2 by A5,A6,TOPREAL3:7 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,width GoB f))`2)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,width GoB f))`2+1 by XCMPLX_1:4 .= 1*((GoB f)*(1,width GoB f))`2+1; then A8: 1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]| = |[(1/2*((GoB f)*(i,width GoB f)+(GoB f)* (i+1,width GoB f))+|[0,1]|)`1, (GoB f)*(1,width GoB f)`2+1]| by EUCLID:57; (1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|)`2 = (1/2*((GoB f)*(i+1,width GoB f)+(GoB f)* (i+2,width GoB f)))`2+|[0,1]|`2 by TOPREAL3:7 .= 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)* (i+2,width GoB f))`2+|[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+|[0,1]|`2 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,width GoB f))`2)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,width GoB f))`2+1 by XCMPLX_1:4 .= 1*((GoB f)*(1,width GoB f))`2+1; then 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]| = |[(1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|)`1, (GoB f)*(1,width GoB f)`2+1]| by EUCLID:57; then p`2 = (GoB f)*(1,width GoB f)`2 + 1 by A3,A8,TOPREAL3:18; hence p`2 > (GoB f)*(1,width GoB f)`2 by REAL_1:69; end; hence LSeg(1/2*((GoB f)*(i,width GoB f)+(GoB f)*(i+1,width GoB f))+|[0,1]|, 1/2*((GoB f)*(i+1,width GoB f)+(GoB f)*(i+2,width GoB f))+|[0,1]|) misses L~f by Th24; end; theorem LSeg((GoB f)*(1,width GoB f)+|[-1,1]|, 1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))+|[0,1]|) misses L~f proof A1: 1 <= width GoB f by GOBOARD7:35; now let p such that A2: p in LSeg((GoB f)*(1,width GoB f)+|[-1,1]|, 1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))+|[0,1]|); 1 < len GoB f by GOBOARD7:34; then 1+1 <= len GoB f by NAT_1:38; then A3: (GoB f)*(2,width GoB f)`2 = (GoB f)*(1,width GoB f)`2 by A1,GOBOARD5: 2; ((GoB f)*(1,width GoB f)+|[-1,1]|)`2 = ((GoB f)*(1,width GoB f))`2+|[-1,1]|`2 by TOPREAL3:7 .= (GoB f)*(1,width GoB f)`2+1 by EUCLID:56; then A4: (GoB f)*(1,width GoB f)+|[-1,1]| = |[((GoB f)*(1,width GoB f)+|[-1,1]|)`1,(GoB f)*(1,width GoB f)`2+1]| by EUCLID:57; (1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))+|[0,1]|)`2 = (1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f)))`2+|[0,1]|`2 by TOPREAL3:7 .= 1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))`2+|[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+|[0,1]|`2 by A3,TOPREAL3:7 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,width GoB f))`2)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,width GoB f))`2+1 by XCMPLX_1:4 .= 1*((GoB f)*(1,width GoB f))`2+1; then 1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))+|[0,1]| = |[(1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))+|[0,1]|)`1, (GoB f)*(1,width GoB f)`2+1]| by EUCLID:57; then p`2 = (GoB f)*(1,width GoB f)`2 + 1 by A2,A4,TOPREAL3:18; hence p`2 > (GoB f)*(1,width GoB f)`2 by REAL_1:69; end; hence LSeg((GoB f)*(1,width GoB f)+|[-1,1]|, 1/2*((GoB f)*(1,width GoB f)+(GoB f)*(2,width GoB f))+|[0,1]|) misses L~f by Th24; end; theorem LSeg(1/2*((GoB f)*(len GoB f -' 1,width GoB f)+ (GoB f)*(len GoB f,width GoB f))+|[0,1]|, (GoB f)*(len GoB f,width GoB f)+|[1,1]|) misses L~f proof A1: 1 <= width GoB f by GOBOARD7:35; now let p such that A2: p in LSeg(1/2*((GoB f)*(len GoB f -' 1,width GoB f)+ (GoB f)*(len GoB f,width GoB f))+|[0,1]|, (GoB f)*(len GoB f,width GoB f)+|[1,1]|); A3: 1 < len GoB f by GOBOARD7:34; then A4: len GoB f -' 1 +1 = len GoB f by AMI_5:4; then A5: 1 <= len GoB f -' 1 by A3,NAT_1:38; len GoB f -' 1 <= len GoB f by A4,NAT_1:29; then A6: (GoB f)*(len GoB f -' 1,width GoB f)`2 = (GoB f)*(1,width GoB f)`2 by A1,A5,GOBOARD5:2; A7: (GoB f)*(len GoB f,width GoB f)`2 = (GoB f)*(1,width GoB f)`2 by A1,A3,GOBOARD5:2; (1/2*((GoB f)*(len GoB f -' 1,width GoB f) +(GoB f)*(len GoB f,width GoB f))+|[0,1]|)`2 = (1/2*((GoB f)*(len GoB f -' 1,width GoB f) +(GoB f)*(len GoB f,width GoB f)))`2+|[0,1]|`2 by TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f -' 1,width GoB f) +(GoB f)*(len GoB f,width GoB f))`2+|[0,1]|`2 by TOPREAL3:9 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+|[0,1]|`2 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(1,width GoB f)`2+(GoB f)*(1,width GoB f)`2)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,width GoB f))`2)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,width GoB f))`2+1 by XCMPLX_1:4 .= 1*((GoB f)*(1,width GoB f))`2+1; then A8: 1/2*((GoB f)*(len GoB f -' 1,width GoB f) +(GoB f)*(len GoB f,width GoB f))+|[0,1]| = |[(1/2*((GoB f)*(len GoB f -' 1,width GoB f) +(GoB f)*(len GoB f,width GoB f))+|[0,1]|)`1, (GoB f)*(1,width GoB f)`2+1]| by EUCLID:57; ((GoB f)*(len GoB f,width GoB f)+|[1,1]|)`2 = (GoB f)*(1,width GoB f)`2+|[1,1]|`2 by A7,TOPREAL3:7 .= (GoB f)*(1,width GoB f)`2+1 by EUCLID:56; then (GoB f)*(len GoB f,width GoB f)+|[1,1]| = |[((GoB f)*(len GoB f,width GoB f)+|[1,1]|)`1, (GoB f)*(1,width GoB f)`2+1]| by EUCLID:57; then p`2 = (GoB f)*(1,width GoB f)`2 + 1 by A2,A8,TOPREAL3:18; hence p`2 > (GoB f)*(1,width GoB f)`2 by REAL_1:69; end; hence LSeg(1/2*((GoB f)*(len GoB f -' 1,width GoB f) +(GoB f)*(len GoB f,width GoB f))+|[0,1]|, (GoB f)*(len GoB f,width GoB f)+|[1,1]|) misses L~f by Th24; end; theorem for j st 1 <= j & j+2 <= width GoB f holds LSeg(1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|, 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|) misses L~f proof let j such that A1: 1 <= j & j+2 <= width GoB f; A2: 1 <= len GoB f by GOBOARD7:34; now let p such that A3: p in LSeg(1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|, 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|); A4: j <= j+2 by NAT_1:29; then j <= width GoB f by A1,AXIOMS:22; then A5: (GoB f)*(1,j)`1 = (GoB f)*(1,1)`1 by A1,A2,GOBOARD5:3; j+1 <= j+2 by AXIOMS:24; then 1 <= j+1 & j+1 <= width GoB f by A1,AXIOMS:22,NAT_1:29; then A6: (GoB f)*(1,j+1)`1 = (GoB f)*(1,1)`1 by A2,GOBOARD5:3; 1 <= j+2 by A1,A4,AXIOMS:22; then A7: (GoB f)*(1,j+2)`1 = (GoB f)*(1,1)`1 by A1,A2,GOBOARD5:3; (1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|)`1 = (1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1)))`1- |[1,0]|`1 by TOPREAL3:8 .= 1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))`1- |[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)- |[1,0]|`1 by A5,A6,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`1)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`1-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`1-1; then A8: 1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]| = |[(GoB f)*(1,1)`1-1, (1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|)`2]| by EUCLID:57; (1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|)`1 = (1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2)))`1- |[1,0]|`1 by TOPREAL3:8 .= 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))`1- |[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)- |[1,0]|`1 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`1)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`1-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`1-1; then 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]| = |[(GoB f)*(1,1)`1-1, (1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|)`2]| by EUCLID:57; then p`1 = (GoB f)*(1,1)`1 - 1 by A3,A8,TOPREAL3:17; hence p`1 < (GoB f)*(1,1)`1 by REAL_2:174; end; hence LSeg(1/2*((GoB f)*(1,j)+(GoB f)*(1,j+1))- |[1,0]|, 1/2*((GoB f)*(1,j+1)+(GoB f)*(1,j+2))- |[1,0]|) misses L~f by Th21; end; theorem LSeg((GoB f)*(1,1)- |[1,1]|,1/2*((GoB f)*(1,1)+(GoB f)*(1,2))- |[1,0]|) misses L~f proof A1: 1 <= len GoB f by GOBOARD7:34; now let p such that A2: p in LSeg((GoB f)*(1,1)- |[1,1]|, 1/2*((GoB f)*(1,1)+(GoB f)*(1,2))- |[1,0]|); 1 < width GoB f by GOBOARD7:35; then 1+1 <= width GoB f by NAT_1:38; then A3: (GoB f)*(1,2)`1 = (GoB f)*(1,1)`1 by A1,GOBOARD5:3; ((GoB f)*(1,1)- |[1,1]|)`1 = ((GoB f)*(1,1))`1- |[1,1]|`1 by TOPREAL3:8 .= (GoB f)*(1,1)`1-1 by EUCLID:56; then A4: (GoB f)*(1,1)- |[1,1]| = |[(GoB f)*(1,1)`1-1,((GoB f)*(1,1)- |[1,1]|)`2]| by EUCLID:57; (1/2*((GoB f)*(1,1)+(GoB f)*(1,2))- |[1,0]|)`1 = (1/2*((GoB f)*(1,1)+(GoB f)*(1,2)))`1- |[1,0]|`1 by TOPREAL3:8 .= 1/2*((GoB f)*(1,1)+(GoB f)*(1,2))`1- |[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)- |[1,0]|`1 by A3,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`1)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`1-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`1-1; then 1/2*((GoB f)*(1,1)+(GoB f)*(1,2))- |[1,0]| = |[(GoB f)*(1,1)`1-1, (1/2*((GoB f)*(1,1)+(GoB f)*(1,2))- |[1,0]|)`2]| by EUCLID:57; then p`1 = (GoB f)*(1,1)`1 - 1 by A2,A4,TOPREAL3:17; hence p`1 < (GoB f)*(1,1)`1 by REAL_2:174; end; hence LSeg((GoB f)*(1,1)- |[1,1]|, 1/2*((GoB f)*(1,1)+(GoB f)*(1,2))- |[1,0]|) misses L~f by Th21; end; theorem LSeg(1/2*((GoB f)*(1,width GoB f -' 1)+(GoB f)*(1,width GoB f))- |[1,0]|, (GoB f)*(1,width GoB f)+|[-1,1]|) misses L~f proof A1: 1 <= len GoB f by GOBOARD7:34; now let p such that A2: p in LSeg(1/2*((GoB f)*(1,width GoB f -' 1)+(GoB f)* (1,width GoB f))- |[1,0]|, (GoB f)*(1,width GoB f)+|[-1,1]|); A3: 1 < width GoB f by GOBOARD7:35; then A4: width GoB f -' 1 +1 = width GoB f by AMI_5:4; then A5: 1 <= width GoB f -' 1 by A3,NAT_1:38; width GoB f -' 1 <= width GoB f by A4,NAT_1:29; then A6: (GoB f)*(1,width GoB f -' 1)`1 = (GoB f)*(1,1)`1 by A1,A5,GOBOARD5:3; A7: (GoB f)*(1,width GoB f)`1 = (GoB f)*(1,1)`1 by A1,A3,GOBOARD5:3; (1/2*((GoB f)*(1,width GoB f -' 1)+(GoB f)*(1,width GoB f))- |[1,0]|)`1 = (1/2*((GoB f)*(1,width GoB f -' 1) +(GoB f)*(1,width GoB f)))`1- |[1,0]|`1 by TOPREAL3:8 .= 1/2*((GoB f)*(1,width GoB f -' 1)+(GoB f)* (1,width GoB f))`1- |[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)- |[1,0]|`1 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(1,1)`1+(GoB f)*(1,1)`1)-1 by EUCLID:56 .= 1/2*(2*((GoB f)*(1,1))`1)-1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(1,1))`1-1 by XCMPLX_1:4 .= 1*((GoB f)*(1,1))`1-1; then A8: 1/2*((GoB f)*(1,width GoB f -' 1)+(GoB f)*(1,width GoB f))- |[1 ,0]| = |[(GoB f)*(1,1)`1-1,(1/2*((GoB f)*(1,width GoB f -' 1) +(GoB f)*(1,width GoB f))- |[1,0]|)`2]| by EUCLID:57; ((GoB f)*(1,width GoB f)+|[-1,1]|)`1 = (GoB f)*(1,1)`1+|[-1,1]|`1 by A7,TOPREAL3:7 .= (GoB f)*(1,1)`1+-1 by EUCLID:56 .= (GoB f)*(1,1)`1-1 by XCMPLX_0:def 8; then (GoB f)*(1,width GoB f)+|[-1,1]| = |[(GoB f)*(1,1)`1-1,((GoB f)* (1,width GoB f)+|[-1,1]|)`2]| by EUCLID:57; then p`1 = (GoB f)*(1,1)`1 - 1 by A2,A8,TOPREAL3:17; hence p`1 < (GoB f)*(1,1)`1 by REAL_2:174; end; hence LSeg(1/2*((GoB f)*(1,width GoB f -' 1)+(GoB f)* (1,width GoB f))- |[1,0]|, (GoB f)*(1,width GoB f)+|[-1,1]|) misses L~f by Th21; end; theorem for j st 1 <= j & j+2 <= width GoB f holds LSeg(1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|, 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|) misses L~f proof let j such that A1: 1 <= j & j+2 <= width GoB f; A2: 1 <= len GoB f by GOBOARD7:34; now let p such that A3: p in LSeg(1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|, 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|); A4: j <= j+2 by NAT_1:29; then j <= width GoB f by A1,AXIOMS:22; then A5: (GoB f)*(len GoB f,j)`1 = (GoB f)*(len GoB f,1)`1 by A1,A2,GOBOARD5:3 ; j+1 <= j+2 by AXIOMS:24; then 1 <= j+1 & j+1 <= width GoB f by A1,AXIOMS:22,NAT_1:29; then A6: (GoB f)*(len GoB f,j+1)`1 = (GoB f)*(len GoB f,1)`1 by A2,GOBOARD5:3; 1 <= j+2 by A1,A4,AXIOMS:22; then A7: (GoB f)*(len GoB f,j+2)`1 = (GoB f)*(len GoB f,1)`1 by A1,A2,GOBOARD5:3; (1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|)`1 = (1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1)))`1+|[1,0]|`1 by TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))`1+|[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+|[1,0]|`1 by A5,A6,TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(len GoB f,1))`1)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(len GoB f,1))`1+1 by XCMPLX_1:4 .= 1*((GoB f)*(len GoB f,1))`1+1; then A8: 1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]| = |[(GoB f)*(len GoB f,1)`1+1,(1/2*((GoB f)*(len GoB f,j) +(GoB f)*(len GoB f,j+1))+|[1,0]|)`2]| by EUCLID:57; (1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|)`1 = (1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2)))`1+|[1,0]|`1 by TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))`1+|[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+|[1,0]|`1 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(len GoB f,1))`1)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(len GoB f,1))`1+1 by XCMPLX_1:4 .= 1*((GoB f)*(len GoB f,1))`1+1; then 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]| = |[(GoB f)*(len GoB f,1)`1+1,(1/2*((GoB f)*(len GoB f,j+1) +(GoB f)*(len GoB f,j+2))+|[1,0]|)`2]| by EUCLID:57; then p`1 = (GoB f)*(len GoB f,1)`1 + 1 by A3,A8,TOPREAL3:17; hence p`1 > (GoB f)*(len GoB f,1)`1 by REAL_1:69; end; hence LSeg(1/2*((GoB f)*(len GoB f,j)+(GoB f)*(len GoB f,j+1))+|[1,0]|, 1/2*((GoB f)*(len GoB f,j+1)+(GoB f)*(len GoB f,j+2))+|[1,0]|) misses L~f by Th22; end; theorem LSeg((GoB f)*(len GoB f,1)+|[1,-1]|, 1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))+|[1,0]|) misses L~f proof A1: 1 <= len GoB f by GOBOARD7:34; now let p such that A2: p in LSeg((GoB f)*(len GoB f,1)+|[1,-1]|, 1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))+|[1,0]|); 1 < width GoB f by GOBOARD7:35; then 1+1 <= width GoB f by NAT_1:38; then A3: (GoB f)*(len GoB f,2)`1 = (GoB f)*(len GoB f,1)`1 by A1,GOBOARD5:3; ((GoB f)*(len GoB f,1)+|[1,-1]|)`1 = ((GoB f)*(len GoB f,1))`1+|[1,-1]|`1 by TOPREAL3:7 .= (GoB f)*(len GoB f,1)`1+1 by EUCLID:56; then A4: (GoB f)*(len GoB f,1)+|[1,-1]| = |[(GoB f)*(len GoB f,1)`1+1,((GoB f)*(len GoB f,1)+|[1,-1]|)`2]| by EUCLID:57; (1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))+|[1,0]|)`1 = (1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2)))`1+|[1,0]|`1 by TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))`1+|[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+|[1,0]|`1 by A3,TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(len GoB f,1))`1)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(len GoB f,1))`1+1 by XCMPLX_1:4 .= 1*((GoB f)*(len GoB f,1))`1+1; then 1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))+|[1,0]| = |[(GoB f)*(len GoB f,1)`1+1, (1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))+|[1,0]|)`2]| by EUCLID:57; then p`1 = (GoB f)*(len GoB f,1)`1 + 1 by A2,A4,TOPREAL3:17; hence p`1 > (GoB f)*(len GoB f,1)`1 by REAL_1:69; end; hence LSeg((GoB f)*(len GoB f,1)+|[1,-1]|, 1/2*((GoB f)*(len GoB f,1)+(GoB f)*(len GoB f,2))+|[1,0]|) misses L~f by Th22; end; theorem LSeg(1/2*((GoB f)*(len GoB f,width GoB f -' 1)+ (GoB f)*(len GoB f,width GoB f))+|[1,0]|, (GoB f)*(len GoB f,width GoB f)+|[1,1]|) misses L~f proof A1: 1 <= len GoB f by GOBOARD7:34; now let p such that A2: p in LSeg(1/2*((GoB f)*(len GoB f,width GoB f -' 1)+ (GoB f)*(len GoB f,width GoB f))+|[1,0]|, (GoB f)*(len GoB f,width GoB f)+|[1,1]|); A3: 1 < width GoB f by GOBOARD7:35; then A4: width GoB f -' 1 +1 = width GoB f by AMI_5:4; then A5: 1 <= width GoB f -' 1 by A3,NAT_1:38; width GoB f -' 1 <= width GoB f by A4,NAT_1:29; then A6: (GoB f)*(len GoB f,width GoB f -' 1)`1 = (GoB f)*(len GoB f,1)`1 by A1,A5,GOBOARD5:3; A7: (GoB f)*(len GoB f,width GoB f)`1 = (GoB f)*(len GoB f,1)`1 by A1,A3,GOBOARD5:3; (1/2*((GoB f)*(len GoB f,width GoB f -' 1) +(GoB f)*(len GoB f,width GoB f))+|[1,0]|)`1 = (1/2*((GoB f)*(len GoB f,width GoB f -' 1) +(GoB f)*(len GoB f,width GoB f)))`1+|[1,0]|`1 by TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,width GoB f -' 1) +(GoB f)*(len GoB f,width GoB f))`1+|[1,0]|`1 by TOPREAL3:9 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+|[1,0]|`1 by A6,A7,TOPREAL3:7 .= 1/2*((GoB f)*(len GoB f,1)`1+(GoB f)*(len GoB f,1)`1)+1 by EUCLID:56 .= 1/2*(2*((GoB f)*(len GoB f,1))`1)+1 by XCMPLX_1:11 .= 1/2*2*((GoB f)*(len GoB f,1))`1+1 by XCMPLX_1:4 .= 1*((GoB f)*(len GoB f,1))`1+1; then A8: 1/2*((GoB f)*(len GoB f,width GoB f -' 1) +(GoB f)*(len GoB f,width GoB f))+|[1,0]| = |[(GoB f)*(len GoB f,1)`1+1,(1/2*((GoB f)* (len GoB f,width GoB f -' 1) +(GoB f)*(len GoB f,width GoB f))+|[1,0]|)`2 ]| by EUCLID:57; ((GoB f)*(len GoB f,width GoB f)+|[1,1]|)`1 = (GoB f)*(len GoB f,1)`1+|[1,1]|`1 by A7,TOPREAL3:7 .= (GoB f)*(len GoB f,1)`1+1 by EUCLID:56; then (GoB f)*(len GoB f,width GoB f)+|[1,1]| = |[(GoB f)*(len GoB f,1)`1+1, ((GoB f)*(len GoB f,width GoB f)+|[1,1]|)`2 ]| by EUCLID:57; then p`1 = (GoB f)*(len GoB f,1)`1 + 1 by A2,A8,TOPREAL3:17; hence p`1 > (GoB f)*(len GoB f,1)`1 by REAL_1:69; end; hence LSeg(1/2*((GoB f)*(len GoB f,width GoB f -' 1) +(GoB f)*(len GoB f,width GoB f))+|[1,0]|, (GoB f)*(len GoB f,width GoB f)+|[1,1]|) misses L~f by Th22; end; theorem 1 <= k & k+1 <= len f implies Int left_cell(f,k) misses L~f proof assume A1: 1 <= k & k+1 <= len f; k <= k+1 by NAT_1:29; then k <= len f by A1,AXIOMS:22; then A2: k in dom f by A1,FINSEQ_3:27; then consider i1,j1 being Nat such that A3: [i1,j1] in Indices GoB f and A4: f/.k = (GoB f)*(i1,j1) by GOBOARD2:25; A5: i1 <= len GoB f by A3,GOBOARD5:1; A6: j1 <= width GoB f by A3,GOBOARD5:1; i1 <> 0 by A3,GOBOARD5:1; then consider i such that A7: i1 = i+1 by NAT_1:22; i <= i1 by A7,NAT_1:29; then A8: i <= len GoB f by A5,AXIOMS:22; j1 <> 0 by A3,GOBOARD5:1; then consider j such that A9: j1 = j+1 by NAT_1:22; j <= j1 by A9,NAT_1:29; then A10: j <= width GoB f by A6,AXIOMS:22; k+1 >= 1 by NAT_1:29; then A11: k+1 in dom f by A1,FINSEQ_3:27; then consider i2,j2 being Nat such that A12: [i2,j2] in Indices GoB f and A13: f/.(k+1) = (GoB f)*(i2,j2) by GOBOARD2:25; A14: i2 <= len GoB f by A12,GOBOARD5:1; A15: j2 <= width GoB f by A12,GOBOARD5:1; abs(i1-i2)+abs(j1-j2) = 1 by A2,A3,A4,A11,A12,A13,GOBOARD5:13; then A16: abs(i1-i2) = 1 & j1 = j2 or abs(j1-j2)=1 & i1 = i2 by GOBOARD1:2; per cases by A16,GOBOARD1:1; suppose i1 = i2 & j1+1 = j2; then left_cell(f,k) = cell(GoB f,i,j1) by A1,A3,A4,A7,A12,A13,GOBOARD5:28; hence thesis by A6,A8,GOBOARD7:14; suppose i1+1 = i2 & j1 = j2; then left_cell(f,k) = cell(GoB f,i1,j1) by A1,A3,A4,A9,A12,A13,GOBOARD5:29; hence thesis by A5,A6,GOBOARD7:14; suppose i1 = i2+1 & j1 = j2; then left_cell(f,k) = cell(GoB f,i2,j) by A1,A3,A4,A9,A12,A13,GOBOARD5:30; hence thesis by A10,A14,GOBOARD7:14; suppose i1 = i2 & j1 = j2+1; then left_cell(f,k) = cell(GoB f,i1,j2) by A1,A3,A4,A7,A12,A13,GOBOARD5:31; hence thesis by A5,A15,GOBOARD7:14; end; theorem 1 <= k & k+1 <= len f implies Int right_cell(f,k) misses L~f proof assume A1: 1 <= k & k+1 <= len f; k <= k+1 by NAT_1:29; then k <= len f by A1,AXIOMS:22; then A2: k in dom f by A1,FINSEQ_3:27; then consider i1,j1 being Nat such that A3: [i1,j1] in Indices GoB f and A4: f/.k = (GoB f)*(i1,j1) by GOBOARD2:25; A5: i1 <= len GoB f by A3,GOBOARD5:1; A6: j1 <= width GoB f by A3,GOBOARD5:1; i1 <> 0 by A3,GOBOARD5:1; then consider i such that A7: i1 = i+1 by NAT_1:22; i <= i1 by A7,NAT_1:29; then A8: i <= len GoB f by A5,AXIOMS:22; j1 <> 0 by A3,GOBOARD5:1; then consider j such that A9: j1 = j+1 by NAT_1:22; j <= j1 by A9,NAT_1:29; then A10: j <= width GoB f by A6,AXIOMS:22; k+1 >= 1 by NAT_1:29; then A11: k+1 in dom f by A1,FINSEQ_3:27; then consider i2,j2 being Nat such that A12: [i2,j2] in Indices GoB f and A13: f/.(k+1) = (GoB f)*(i2,j2) by GOBOARD2:25; A14: i2 <= len GoB f by A12,GOBOARD5:1; A15: j2 <= width GoB f by A12,GOBOARD5:1; abs(i1-i2)+abs(j1-j2) = 1 by A2,A3,A4,A11,A12,A13,GOBOARD5:13; then A16: abs(i1-i2) = 1 & j1 = j2 or abs(j1-j2)=1 & i1 = i2 by GOBOARD1:2; per cases by A16,GOBOARD1:1; suppose i1 = i2 & j1+1 = j2; then right_cell(f,k) = cell(GoB f,i1,j1) by A1,A3,A4,A7,A12,A13,GOBOARD5:28 ; hence thesis by A5,A6,GOBOARD7:14; suppose i1+1 = i2 & j1 = j2; then right_cell(f,k) = cell(GoB f,i1,j) by A1,A3,A4,A9,A12,A13,GOBOARD5:29; hence thesis by A5,A10,GOBOARD7:14; suppose i1 = i2+1 & j1 = j2; then right_cell(f,k) = cell(GoB f,i2,j1) by A1,A3,A4,A9,A12,A13,GOBOARD5:30 ; hence thesis by A6,A14,GOBOARD7:14; suppose i1 = i2 & j1 = j2+1; then right_cell(f,k) = cell(GoB f,i,j2) by A1,A3,A4,A7,A12,A13,GOBOARD5:31; hence thesis by A8,A15,GOBOARD7:14; end;