Copyright (c) 1990 Association of Mizar Users
environ vocabulary DIRAF, VECTSP_1, ANALOAF, PASCH, FUNCT_2, TRANSGEO, FUNCT_1, AFF_2, INCSP_1, AFF_1, RELAT_1; notation PARTFUN1, FUNCT_2, STRUCT_0, ANALOAF, DIRAF, AFF_1, AFF_2, TRANSGEO; constructors AFF_1, AFF_2, TRANSGEO, MEMBERED, PARTFUN1, RELAT_2, XBOOLE_0; clusters STRUCT_0, RELSET_1, FUNCT_2, MEMBERED, ZFMISC_1, PARTFUN1, FUNCT_1, XBOOLE_0; requirements SUBSET, BOOLE; theorems FUNCT_2, TRANSGEO, AFF_1, AFF_2, FUNCT_1, DIRAF, RELAT_1; schemes TRANSGEO; begin reserve AS for AffinSpace, a,b,c,d,p,q,r,s,x for Element of AS; definition let AS; attr AS is Fanoian means :Def1: for a,b,c,d st a,b // c,d & a,c // b,d & a,d // b,c holds LIN a,b,c; synonym AS satisfies_Fano; end; Lm1: (LIN a,b,c & a<>b & a<>c & b<>c & not LIN a,b,p) implies (ex x st LIN p,a,x & p<>x & a<>x) proof assume A1: LIN a,b,c & a<>b & a<>c & b<>c & not LIN a,b,p; then a,b // a,c by AFF_1:def 1; then b,a // a,c by AFF_1:13; then consider x such that A2: p,a // a,x & p,b // c,x by A1,DIRAF:47; a,p // a,x by A2,AFF_1:13; then LIN a,p,x by AFF_1:def 1; then A3: LIN p,a,x by AFF_1:15; A4: now assume p = x; then p,b // p,c by A2,AFF_1:13; then LIN p,b,c by AFF_1:def 1; then LIN b,c,p & LIN b,c,a & LIN b,c,b by A1,AFF_1:15,16; hence contradiction by A1,AFF_1:17; end; now assume a = x; then p,b // a,c & a,b // a,c by A1,A2,AFF_1:13,def 1; then a,b // p,b by A1,AFF_1:14; then b,a // b,p by AFF_1:13; then LIN b,a,p by AFF_1:def 1; hence contradiction by A1,AFF_1:15; end; hence thesis by A3,A4; end; Lm2: (LIN a,b,c & a<>b & a<>c & b<>c & not LIN a,b,p & LIN a,b,q) implies (ex x st LIN p,q,x & p<>x & q<>x) proof assume A1: LIN a,b,c & a<>b & a<>c & b<>c & not LIN a,b,p & LIN a,b,q; A2: now assume A3: q = b & q<>a & q<>c; then LIN q,a,c & not LIN q,a,p by A1,AFF_1:15; hence thesis by A1,A3,Lm1; end; A4: now assume A5: q = c & q<>a & q<>b; now assume LIN q,a,p; then LIN c,a,p & LIN c,a,b & LIN c,a,a by A1,A5,AFF_1:15,16; hence contradiction by A1,AFF_1:17; end; then LIN q,a,b & not LIN q,a,p by A1,AFF_1:15; hence thesis by A1,A5,Lm1; end; now assume A6: q<>a & q<>b & q<>c; now assume LIN q,a,p; then LIN a,q,p & LIN a,q,b by A1,AFF_1:15; then a,q // a,p & a,q // a,b by AFF_1:def 1; then a,b // a,p by A6,AFF_1: 14; hence contradiction by A1,AFF_1:def 1; end; then LIN q,a,b & not LIN q,a,p by A1,AFF_1:15; hence thesis by A1,A6,Lm1; end; hence thesis by A1,A2,A4,Lm1; end; Lm3: (LIN a,b,c & a<>b & a<>c & b<>c & not LIN a,b,p & p<>q & p,q // a,b) implies (ex x st LIN p,q,x & p<>x & q<>x) proof assume A1: LIN a,b,c & a<>b & a<>c & b<>c & not LIN a,b,p & p<>q & p,q // a,b; A2: a<>q proof assume a = q; then a,p // a,b by A1,AFF_1:13; then LIN a,p,b by AFF_1:def 1; hence contradiction by A1,AFF_1:15; end; A3: b<>q proof assume b = q; then b,p // b,a by A1,AFF_1:13; then LIN b,p,a by AFF_1:def 1; hence contradiction by A1,AFF_1:15; end; A4: not LIN a,b,q proof assume A5: LIN a,b,q; then a,b // a,q by AFF_1:def 1 ; then p,q // a,q by A1,AFF_1:14; then q,p // q,a by AFF_1:13; then LIN q,p,a by AFF_1:def 1; then LIN q,a,p & LIN q,a,b & LIN q,a,a by A5,AFF_1:15,16; hence contradiction by A1,A2,AFF_1:17; end; A6: not LIN a,c,p proof assume LIN a,c,p; then LIN a,c,p & LIN a,c,b & LIN a,c,a by A1,AFF_1:15,16; hence contradiction by A1,AFF_1:17; end; consider r such that A7: b,c // q,r & b,q // c,r by DIRAF:47; LIN b,a,c by A1,AFF_1:15; then b,a // b,c by AFF_1:def 1; then b,a // q,r by A1,A7,AFF_1:14; then a,b // q,r by AFF_1:13; then p,q // q,r by A1,AFF_1:14; then q,p // q,r by AFF_1:13; then LIN q,p,r by AFF_1:def 1; then A8: LIN p,q,r by AFF_1:15; A9: q<>r proof assume q = r; then q,b // q,c by A7,AFF_1:13; then LIN q,b,c by AFF_1:def 1; then LIN b,c,q & LIN b,c,a & LIN b,c,b by A1,AFF_1:15,16; hence contradiction by A1,A4,AFF_1:17; end; now assume A10: p = r; consider s such that A11: b,a // q,s & b,q // a,s by DIRAF:47; A12: now assume p = s; then a,p // c,p by A3,A7,A10,A11,AFF_1:14; then p,a // p,c by AFF_1:13; then LIN p,a,c by AFF_1:def 1; hence contradiction by A6,AFF_1:15; end; A13: q<>s proof assume q = s; then q,b // q,a by A11,AFF_1:13; then LIN q,b,a by AFF_1:def 1; hence contradiction by A4,AFF_1:15; end; a,b // q,s by A11,AFF_1:13; then p,q // q,s by A1,AFF_1:14; then q,p // q,s by AFF_1:13; then LIN q,p,s by AFF_1:def 1; then LIN p,q,s by AFF_1:15; hence thesis by A12,A13; end; hence thesis by A8,A9; end; canceled; theorem Th2: (ex a,b,c st LIN a,b,c & a<>b & a<>c & b<>c) implies (for p,q st p<>q holds (ex r st LIN p,q,r & p<>r & q<>r)) proof given a,b,c such that A1: LIN a,b,c & a<>b & a<>c & b<>c; let p,q such that A2: p<>q; A3: now assume A4: LIN a,b,p & LIN a,b,q; then A5: LIN p,q,c by A1,AFF_1:17; LIN a,b,a & LIN a,b,b by AFF_1:16; then A6: LIN p,q,a & LIN p,q,b by A1,A4,AFF_1:17; now assume A7: p = c or q = c; now assume p <> a or q <> b; A8: now assume A9: p = c & p<>a; then q = b implies thesis by A1,A6; hence thesis by A1,A6,A9; end; now assume A10: q = c & q<>b; then p = b implies thesis by A1,A6; hence thesis by A6,A10; end; hence thesis by A1,A7,A8; end; hence thesis by A1; end; hence thesis by A5; end; A11: now assume not LIN a,b,q & LIN a,b,p; then consider x such that A12: LIN q,p,x & q<>x & p<>x by A1,Lm2; LIN p,q,x by A12,AFF_1:15; hence thesis by A12; end; now assume A13: not LIN a,b,p & not LIN a,b,q; now assume A14: not p,q // a,b; consider p' being Element of AS such that A15: a,b // p,p' & p<>p' by DIRAF:47; p,p' // a,b by A15,AFF_1:13; then A16: ex p'' being Element of AS st LIN p,p',p'' & p<>p'' & p'<>p'' by A1,A13,A15,Lm3; not LIN p,p',q proof assume LIN p,p',q; then p,p' // p,q by AFF_1:def 1 ; hence contradiction by A14,A15,AFF_1:14; end; then consider r such that A17: LIN q,p,r & q<>r & p<>r by A15,A16,Lm1; LIN p,q,r by A17,AFF_1:15; hence thesis by A17; end; hence thesis by A1,A2,A13,Lm3; end; hence thesis by A1,A3,A11,Lm2; end; reserve AFP for AffinPlane, a,a',b,b',c,c',d,p,p',q,q',r,x,x',y,y',z for Element of AFP, A,C,P for Subset of AFP, f,g,h,f1,f2 for Permutation of the carrier of AFP; canceled; theorem Th4: (AFP satisfies_Fano & a,b // c,d & a,c // b,d & not LIN a,b,c) implies ex p st LIN b,c,p & LIN a,d,p proof assume that A1: for a,b,c,d st a,b // c,d & a,c // b,d & a,d // b,c holds LIN a,b,c and A2: a,b // c,d & a,c // b,d & not LIN a,b,c; not a,d // b,c by A1,A2; then ex p st LIN a,d,p & LIN b,c,p by AFF_1:74; hence thesis; end; Lm4: not LIN a,b,x & a,b // x,y & x<>y implies not LIN x,y,a & not LIN b,a,y & not LIN y,x,b proof assume that A1: not LIN a,b,x and A2: a,b // x,y and A3: x<>y; thus not LIN x,y,a proof assume LIN x,y,a; then LIN x,y,a & x,y // a,b by A2,AFF_1:13; then LIN x,y,a & LIN x,y,b & LIN x,y,x by A3,AFF_1:16,18; hence contradiction by A1,A3,AFF_1:17; end; thus not LIN b,a,y proof assume LIN b,a,y; then LIN b,a,y & b,a // y,x & b<>a by A1,A2,AFF_1:13,16; then LIN b,a,x by AFF_1:18; hence contradiction by A1,AFF_1:15; end; thus not LIN y,x,b proof assume LIN y,x,b; then LIN y,x,b & y,x // b,a by A2,AFF_1:13; then LIN y,x,b & LIN y,x,a & LIN y,x,x by A3,AFF_1:16,18; hence contradiction by A1,A3,AFF_1:17; end; end; Lm5: not LIN a,b,x & a,b // x,y & a,x // b,y implies not LIN x,y,a & not LIN b,a,y & not LIN y,x,b proof assume that A1: not LIN a,b,x and A2: a,b // x,y & a,x // b,y; x<>y proof assume x=y; then x,a // x,b by A2,AFF_1:13; then LIN x,a,b by AFF_1:def 1; hence contradiction by A1,AFF_1:15; end; hence thesis by A1,A2,Lm4; end; theorem Th5: f is_Tr & not LIN a,f.a,x & a,f.a // x,y & a,x // f.a,y implies y=f.x proof assume A1: f is_Tr; then A2: f is_Dil by TRANSGEO:def 11; assume A3: not LIN a,f.a,x & a,f.a // x,y & a,x // f.a,y; a,x // f.a,f.x & a,f.a // x,f.x by A1,A2,TRANSGEO:85,100; hence thesis by A3,TRANSGEO:97; end; theorem Th6: AFP satisfies_des iff (for a,a',b,c,b',c' st not LIN a,a',b & not LIN a,a',c & a,a' // b,b' & a,a' // c,c' & a,b // a',b' & a,c // a',c' holds b,c // b',c') proof thus AFP satisfies_des implies (for a,a',b,c,b',c' st not LIN a,a',b & not LIN a,a',c & a,a' // b,b' & a,a' // c,c' & a,b // a',b' & a,c // a',c' holds b,c // b',c') proof assume A1: AFP satisfies_des; let a,a',b,c,b',c'; assume A2: not LIN a,a',b & not LIN a,a',c & a,a' // b,b' & a,a' // c,c' & a,b // a',b' & a,c // a',c'; set A=Line(a,a'), P=Line(b,b'), C=Line(c,c'); A3: a<>a' & a<>b & a'<>b & a<>c & a'<>c by A2,AFF_1:16; A4: b<>b' proof assume b=b'; then b,a // b,a' by A2,AFF_1:13; then LIN b,a,a' by AFF_1:def 1; hence contradiction by A2,AFF_1:15; end; A5: c <>c' proof assume c = c'; then c,a // c,a' by A2,AFF_1:13; then LIN c,a,a' by AFF_1:def 1; hence contradiction by A2,AFF_1:15; end; A6: a in A & a' in A & b in P & b' in P & c in C & c' in C by AFF_1:26; A7: A is_line & P is_line & C is_line by A3,A4,A5,AFF_1:def 3; A8: A // P & A // C by A2,A3,A4,A5,AFF_1:51; A9: A<>P by A2,A6,A7,AFF_1:33; A<>C by A2,A6,A7,AFF_1:33; hence thesis by A1,A2,A6,A7,A8,A9,AFF_2:def 11; end; assume A10: for a,a',b,c,b',c' st not LIN a,a',b & not LIN a,a',c & a,a' // b,b' & a,a' // c,c' & a,b // a',b' & a,c // a',c' holds b,c // b',c'; now let A,P,C,a,b,c,a',b',c'; assume A11: A // P & A // C & a in A & a' in A & b in P & b' in P & c in C & c' in C & A is_line & P is_line & C is_line & A<>P & A<>C & a,b // a',b' & a,c // a',c'; then A12: a,a' // b,b' & a,a' // c,c' by AFF_1:53; A13: now assume A14: a=a'; then LIN a,b,b' by A11,AFF_1:def 1; then LIN b,b',a by AFF_1:15; then A15: b=b' or a in P by A11,AFF_1:39; LIN a,c,c' by A11,A14,AFF_1:def 1; then LIN c,c',a by AFF_1:15; then c = c' or a in C by A11,AFF_1:39; hence b,c // b',c' by A11,A15,AFF_1:11,59; end; now assume A16: a<>a'; A17: not LIN a,a',b proof assume LIN a,a',b; then b in A by A11,A16,AFF_1:39; hence contradiction by A11,AFF_1:59; end; not LIN a,a',c proof assume LIN a,a',c; then c in A by A11,A16,AFF_1:39; hence contradiction by A11,AFF_1:59; end; hence b,c // b',c' by A10,A11,A12,A17; end; hence b,c // b',c' by A13; end; hence thesis by AFF_2:def 11; end; theorem Th7: ex f st f is_Tr & f.a=a proof take id the carrier of AFP; thus thesis by FUNCT_1:35,TRANSGEO:99; end; Lm6: a<>b implies ex y st ((not LIN a,b,x & a,b // x,y & a,x // b,y) or (LIN a,b,x & ex p,q st not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // x,y & p,x // q,y)) proof assume A1: a<>b; A2: now assume A3: not LIN a,b,x; ex y st a,b // x,y & a,x // b,y by DIRAF:47; hence thesis by A3; end; now assume A4: LIN a,b,x; consider p such that A5: not LIN a,b,p by A1,AFF_1:22; consider q such that A6: a,b // p,q & a,p // b,q by DIRAF:47; ex y st p,q // x,y & p,x // q,y by DIRAF:47; hence thesis by A4,A5,A6; end; hence thesis by A2; end; Lm7: a<>b implies ex x st (not LIN a,b,x & a,b // x,y & a,x // b,y) or (LIN a,b,x & (ex p,q st not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // x,y & p,x // q,y)) proof assume A1: a<>b; A2: now assume not LIN a,b,y; then A3: not LIN b,a,y by AFF_1:15; consider x such that A4: b,a // y,x & b,y // a,x by DIRAF:47; A5: not LIN a,b,x by A3,A4,Lm5; a,b // x,y & a,x // b,y by A4,AFF_1:13; hence thesis by A5; end; now assume A6: LIN a,b,y; consider p such that A7: not LIN a,b,p by A1,AFF_1:22; consider q such that A8: a,b // p,q & a,p // b,q by DIRAF:47; consider x such that A9: q,p // y,x & q,y // p,x by DIRAF:47; A10: p,q // x,y & p,x // q,y by A9,AFF_1:13; LIN a,b,x proof A11: a,b // x,y or p=q by A8,A10,AFF_1:14; now assume p=q; then p,a // p,b by A8,AFF_1:13; then LIN p,a,b by AFF_1:def 1; hence contradiction by A7,AFF_1:15; end; then a,b // y,x by A11,AFF_1:13; hence LIN a,b,x by A1,A6,AFF_1:18; end; hence thesis by A7,A8,A10; end; hence thesis by A2; end; Lm8: AFP satisfies_des & a<>b & LIN a,b,x & a,b // p,q & a,b // p',q' & a,p // b,q & a,p' // b,q' & p,q // x,y & p',q' // x,y' & p,x // q,y & p',x // q',y' & not LIN a,b,p & not LIN a,b,p' & not LIN p,q,p' implies y=y' proof assume that A1: AFP satisfies_des and A2: a<>b and A3: LIN a,b,x and A4: a,b // p,q and A5: a,b // p',q' and A6: a,p // b,q and A7: a,p' // b,q' and A8: p,q // x,y and A9: p',q' // x,y' and A10: p,x // q,y and A11: p',x // q',y' and A12: not LIN a,b,p and A13: not LIN a,b,p' and A14: not LIN p,q,p'; A15: p,p' // q,q' by A1,A4,A5,A6,A7,A12,A13,Th6; A16: p,q // p',q' by A2,A4,A5,AFF_1:14; A17: p<>q proof assume p=q; then p,a // p,b by A6,AFF_1:13; then LIN p,a,b by AFF_1:def 1; hence contradiction by A12,AFF_1:15; end; A18: p'<>q' proof assume p'=q'; then p',a // p',b by A7,AFF_1:13; then LIN p',a,b by AFF_1:def 1; hence contradiction by A13,AFF_1:15; end; not LIN p,q,x proof assume A19: LIN p,q,x; then A20: p,q // p,x by AFF_1:def 1; A21: x<>a by A4,A6,A12,A19,Lm5; p,x // a,b & a,b // a,x by A3,A4,A17,A20,AFF_1:14,def 1; then p,x // a,x by A2,AFF_1:14; then x,p // x,a by AFF_1:13; then LIN x,p,a & LIN x,p,x & LIN a,x,b by A3,AFF_1:15,16,def 1; then LIN x,p,a & LIN x,p,b & LIN x,p,p by A21,AFF_1:16,20; hence contradiction by A3,A12,AFF_1:17; end; then A22: p',x // q',y by A1,A8,A10,A14,A15,A16,Th6; A23: not LIN p',q',x proof assume A24: LIN p',q',x; then A25: p',q' // p',x by AFF_1:def 1; A26: x<>a by A5,A7,A13,A24,Lm5; p',x // a,b & a,b // a,x by A3,A5,A18,A25,AFF_1:14,def 1; then p',x // a,x by A2,AFF_1:14; then x,p' // x,a by AFF_1:13; then LIN x,p',a & LIN x,p',x & LIN a,x,b by A3,AFF_1:15,16,def 1; then LIN x,p',a & LIN x,p',b & LIN x,p',p' by A26,AFF_1:16,20; hence contradiction by A3,A13,AFF_1:17; end; p',q' // x,y by A8,A16,A17,AFF_1:14; hence thesis by A9,A11,A22,A23,TRANSGEO:97; end; theorem Th8: (for p,q,r st p<>q & LIN p,q,r holds r = p or r = q) & a,b // p,q & a,p // b,q & not LIN a,b,p implies a,q // b,p proof assume that A1: for p,q,r st p<>q & LIN p,q,r holds r = p or r = q and A2: a,b // p,q & a,p // b,q & not LIN a,b,p; A3: a<>b & a<>p & b<>p by A2,AFF_1:16; A4: p<>q proof assume p=q; then p,a // p,b by A2,AFF_1:13; then LIN p,a,b by AFF_1:def 1; hence contradiction by A2,AFF_1:15; end; A5: not LIN a,p,q proof assume LIN a,p,q; then LIN p,q,a & p,q // a,b by A2,AFF_1:13,15; then LIN p,q,b & LIN p,q,a & LIN p,q,p by A4,AFF_1:16,18; hence contradiction by A2,A4,AFF_1:17; end; consider z such that A6: q,p // a,z & q,a // p,z by DIRAF:47; p,q // a,z by A6,AFF_1:13; then a,b // a,z by A2,A4,AFF_1:14; then LIN a,b,z by AFF_1:def 1; then A7: a=z or b=z by A1,A3; now assume a=z; then a,p // a,q by A6,AFF_1:13; hence contradiction by A5,AFF_1:def 1; end;hence thesis by A6,A7,AFF_1:13 ; end; Lm9: AFP satisfies_des & a<>b & LIN a,b,x & a,b // p,q & a,b // p',q' & a,p // b,q & a,p' // b,q' & p,q // x,y & p',q' // x,y' & p,x // q,y & p',x // q',y' & not LIN a,b,p & not LIN a,b,p' implies y=y' proof assume A1: AFP satisfies_des & a<>b & LIN a,b,x & a,b // p,q & a,b // p',q' & a,p // b,q & a,p' // b,q' & p,q // x,y & p',q' // x,y' & p,x // q,y & p',x // q',y' & not LIN a,b,p & not LIN a,b,p'; then A2: a<>p & a<>p' by AFF_1:16; A3: p<>q proof assume p=q; then p,a // p,b by A1,AFF_1:13; then LIN p,a,b by AFF_1:def 1; hence contradiction by A1,AFF_1:15; end; A4: p'<>q' proof assume p'=q'; then p',a // p',b by A1,AFF_1:13; then LIN p',a,b by AFF_1:def 1; hence contradiction by A1,AFF_1:15; end; A5: not LIN p,q,x proof assume LIN p,q,x; then p,q // p,x by AFF_1:def 1; then a,b // p,x by A1,A3,AFF_1:14; then a,b // x,p by AFF_1:13; hence contradiction by A1,AFF_1:18; end; A6: not LIN p',q',x proof assume LIN p',q',x; then p',q' // p',x by AFF_1:def 1; then a,b // p',x by A1,A4,AFF_1:14; then a,b // x,p' by AFF_1:13; hence contradiction by A1,AFF_1:18; end; A7: x<>y & x<>y' proof now assume x=y; then x,p // x,q by A1,AFF_1:13; then LIN x,p,q by AFF_1:def 1; hence contradiction by A5,AFF_1:15; end; hence x<>y; now assume x=y'; then x,p' // x,q' by A1,AFF_1:13; then LIN x,p',q' by AFF_1:def 1; hence contradiction by A6,AFF_1:15; end; hence x<>y'; end; A8: LIN a,b,y proof a,b // x,y by A1,A3,AFF_1:14; hence thesis by A1,AFF_1:18; end; A9: not LIN q,p,b proof assume A10: LIN q,p,b; q,p // b,a by A1,AFF_1:13; then LIN q,p,a & LIN q,p,p by A3,A10,AFF_1:16,18; hence contradiction by A1,A3,A10,AFF_1:17; end; now assume A11: LIN p,q,p'; A12: LIN p,q,q' proof p,q // p',q' by A1,AFF_1:14; hence LIN p,q,q' by A3,A11,AFF_1:18; end; A13: now assume A14:for x st LIN a,p,x holds x=a or x=p; then A15: for p,q,r st p<>q & LIN p,q,r holds r = p or r = q by A2,Th2; A16: now assume A17: p=p'; then q=q' by A2,A3,A4,A12,A14,Th2; hence y=y' by A1,A5,A17,TRANSGEO:97; end; now assume A18: q=p'; A19: now assume A20: a=x; then A21: b=y by A1,A7,A8,A14,Th2; a,q // b,p by A1,A15,Th8; then A22: q,p // a,b & q,a // p,b by A1,AFF_1:13; A23: q,p // a,y' & q,a // p,y' by A1,A3,A4,A12,A14,A18,A20,Th2; not LIN q,p,a by A5,A20,AFF_1:15; hence y=y' by A21,A22,A23,TRANSGEO:97; end; now assume A24: b=x; then A25: a=y by A1,A2,A7,A8,A14,Th2; q,p // b,a & q,p // b,y' & q,b // p,a & q,b // p,y' by A1,A2,A3,A4,A12,A14,A18,A24,Th2,AFF_1:13; hence y=y' by A9,A25,TRANSGEO:97; end; hence y=y' by A1,A2,A14,A19,Th2; end; hence y=y' by A2,A3,A11,A14,A16,Th2; end; now given p'' being Element of AFP such that A26: LIN a,p,p'' & p''<>a & p''<>p; consider q'' being Element of AFP such that A27: a,b // p'',q'' and A28: a,p'' // b,q'' by DIRAF:47; consider y'' being Element of AFP such that A29: p'',q'' // x,y'' and A30: p'',x // q'',y'' by DIRAF:47; A31: not LIN p,q,p'' proof assume LIN p,q,p''; then LIN p,p'',p & LIN p,p'',q & LIN p,p'',a by A26,AFF_1:15,16; then LIN p,q,a by A26,AFF_1:17; hence contradiction by A1,Lm5; end; A32: not LIN p',q',p'' proof assume A33: LIN p',q',p''; p,q // p',q' by A1,AFF_1:14; then LIN p,q,q' by A3,A11,AFF_1:18; hence contradiction by A4,A11,A31,A33,AFF_1:20; end; not LIN a,b,p'' proof assume LIN a,b,p''; then LIN a,p'',a & LIN a,p'',b & LIN a,p'',p by A26,AFF_1:15,16; hence contradiction by A1,A26,AFF_1:17; end; then y=y'' & y'=y'' by A1,A27,A28,A29,A30,A31,A32,Lm8; hence y=y'; end; hence y=y' by A13; end; hence thesis by A1,Lm8; end; Lm10: a<>b & LIN a,b,x & a,b // p,q & a,p // b,q & p,q // x,y & not LIN a,b,p implies p<>q & LIN a,b,y proof assume that A1: a<>b and A2: LIN a,b,x and A3: a,b // p,q and A4: a,p // b,q and A5: p,q // x,y and A6: not LIN a,b,p; thus p<>q proof assume p=q; then p,a // p,b by A4,AFF_1:13; then LIN p,a,b by AFF_1:def 1; hence contradiction by A6,AFF_1:15; end; then a,b // x,y by A3,A5,AFF_1:14; hence LIN a,b,y by A1,A2,AFF_1:18; end; Lm11: AFP satisfies_des & a<>b & LIN a,b,x & a,b // p,q & a,b // p',q' & a,p // b,q & a,p' // b,q' & p,q // x,y & p,x // q,y & p',q' // x',y & p',x' // q',y & not LIN a,b,p & not LIN a,b,p' implies x=x' proof assume that A1: AFP satisfies_des and A2: a<>b and A3: LIN a,b,x and A4: a,b // p,q and A5: a,b // p',q' and A6: a,p // b,q and A7: a,p' // b,q' and A8: p,q // x,y and A9: p,x // q,y and A10: p',q' // x',y and A11: p',x' // q',y and A12: not LIN a,b,p and A13: not LIN a,b,p'; LIN a,b,y by A2,A3,A4,A6,A8,A12,Lm10; then A14: LIN b,a,y by AFF_1:15; A15: b,a // q,p by A4,AFF_1:13; A16: b,a // q',p' by A5,AFF_1:13; A17: b,q // a,p by A6,AFF_1:13; A18: b,q' // a,p' by A7,AFF_1:13; A19: q,p // y,x by A8,AFF_1:13; A20: q,y // p,x by A9,AFF_1:13; A21: q',p' // y,x' by A10,AFF_1:13; A22: q',y // p',x' by A11,AFF_1:13; A23: not LIN b,a,q by A4,A6,A12,Lm5; not LIN b,a,q' by A5,A7,A13,Lm5; hence x=x' by A1,A2,A14,A15,A16,A17,A18,A19,A20,A21,A22,A23,Lm9; end; Lm12: AFP satisfies_des & a<>b implies ex f st f is_Tr & f.a=b proof defpred X[Element of AFP,Element of AFP] means (not LIN a,b,$1 & a,b // $1,$2 & a,$1 // b,$2) or (LIN a,b,$1 & (ex p,q st not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // $1,$2 & p,$1 // q,$2)); assume A1: AFP satisfies_des & a<>b; then A2: ex y st X[x,y] by Lm6; A3: ex x st X[x,y] by A1,Lm7; A4: X[x,y] & X[x,y'] implies y=y' by A1,Lm9,TRANSGEO:97; A5: X[x,y] & X[x',y] implies x=x' proof assume A6:((not LIN a,b,x & a,b // x,y & a,x // b,y) or (LIN a,b,x & ex p,q st not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // x,y & p,x // q,y)) & ((not LIN a,b,x' & a,b // x',y & a,x' // b,y) or (LIN a,b,x' & ex p,q st not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // x',y & p,x' // q,y)); A7: now assume A8: not LIN a,b,y; then A9: not LIN b,a,y by A1,A6,Lm5,Lm10; A10: b,a // y,x & b,y // a,x by A1,A6,A8,Lm10,AFF_1:13; b,a // y,x' & b,y // a,x' by A1,A6,A8,Lm10,AFF_1:13; hence x=x' by A9,A10,TRANSGEO:97; end; now assume A11: LIN a,b,y; A12: not (not LIN a,b,x & a,b // x,y & a,x // b,y) proof assume A13: not LIN a,b,x & a,b // x,y & a,x // b,y; then a,b // y,x by AFF_1:13; hence contradiction by A1,A11,A13,AFF_1:18; end; not (not LIN a,b,x' & a,b // x',y & a,x' // b,y) proof assume A14: not LIN a,b,x' & a,b // x',y & a,x' // b,y; then a,b // y,x' by AFF_1:13; hence contradiction by A1,A11,A14,AFF_1:18; end; hence x=x' by A1,A6,A12,Lm11; end; hence x=x' by A7; end; ex f st for x,y holds f.x=y iff X[x,y] from EXPermutation(A2,A3,A5,A4); then consider f such that A15: for x,y holds f.x=y iff (not LIN a,b,x & a,b // x,y & a,x // b,y) or (LIN a,b,x & (ex p,q st not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // x,y & p,x // q,y)); A16: a,b // x,f.x proof set y=f.x; now assume A17: LIN a,b,x; then consider p,q such that A18: not LIN a,b,p & a,b // p,q & a,p // b,q & p,q // x,y & p,x // q,y by A15; p<>q by A1,A17,A18,Lm10; hence a,b // x,f.x by A18,AFF_1:14; end; hence a,b // x,f.x by A15; end; A19: x,f.x // y,f.y proof a,b // x,f.x & a,b // y,f.y by A16; hence x,f.x // y,f.y by A1,AFF_1:14; end; for x,y holds x,y // f.x,f.y proof let x,y; A20: now assume A21: not LIN a,b,x & not LIN a,b,y; then a,x // b,f.x & a,y // b,f.y & a,b // x,f.x & a,b // y,f.y by A15; hence thesis by A1,A21,Th6; end; A22: now assume A23: LIN a,b,x & LIN a,b,y; then A24: a,b // x,y by AFF_1:19; a,b // x,f.x & a,b // y,f.y by A16; then LIN a,b,f.x & LIN a,b,f.y by A1,A23,AFF_1:18; then a,b // f.x,f.y by AFF_1:19; hence thesis by A1,A24,AFF_1:14; end; A25: now assume A26: LIN a,b,x & not LIN a,b,y; then A27: a,b // y,f.y & a,y // b,f.y by A15; ex x' st y,f.y // x,x' & y,x // f.y,x' by DIRAF:47; then y,x // f.y,f.x by A15,A26,A27; hence thesis by AFF_1:13; end; now assume A28: not LIN a,b,x & LIN a,b,y; then A29: a,b // x,f.x & a,x // b,f.x by A15; ex y' st x,f.x // y,y' & x,y // f.x,y' by DIRAF:47; hence thesis by A15,A28,A29; end; hence thesis by A20,A22,A25; end; then f is_Dil by TRANSGEO:85; then A30: f is_Tr by A19,TRANSGEO:100; f.a=b proof consider p such that A31: not LIN a,b,p by A1,AFF_1:22; consider q such that A32: a,b // p,q & a,p // b,q by DIRAF:47; A33: p,q // a,b & p,a // q,b by A32,AFF_1:13; p,q // a,b & LIN a,b,a by A32,AFF_1:13,16; hence f.a=b by A15,A31,A32,A33; end; hence thesis by A30; end; theorem Th9: AFP satisfies_des implies ex f st f is_Tr & f.a=b proof assume A1: AFP satisfies_des; a=b implies thesis by Th7; hence thesis by A1,Lm12; end; theorem (for a,b ex f st f is_Tr & f.a=b) implies AFP satisfies_des proof assume A1: for a,b ex f st f is_Tr & f.a=b; now let a,a',b,c,b',c'; assume A2: not LIN a,a',b & not LIN a,a',c & a,a' // b,b' & a,a' // c,c' & a,b // a',b' & a,c // a',c'; consider f such that A3: f is_Tr and A4: f.a=a' by A1; A5: b'=f.b by A2,A3,A4,Th5; A6: c'=f.c by A2,A3,A4,Th5; f is_Dil by A3,TRANSGEO:def 11; hence b,c // b',c' by A5,A6,TRANSGEO:85; end; hence thesis by Th6; end; theorem Th11: f is_Tr & g is_Tr & not LIN a,f.a,g.a implies f*g=g*f proof assume A1: f is_Tr & g is_Tr; assume A2: not LIN a,f.a,g.a; A3: f is_Dil & g is_Dil by A1,TRANSGEO:def 11; then A4: a,f.a // g.a,g.(f.a) by TRANSGEO:85; a,g.a // f.a,g.(f.a) by A1,A3,TRANSGEO:100; then f.(g.a)=g.(f.a) by A1,A2,A4,Th5; then (f*g).a=g.(f.a) by FUNCT_2:70; then A5: (f*g).a=(g*f).a by FUNCT_2:70; f*g is_Tr & g*f is_Tr by A1,TRANSGEO:105; hence thesis by A5,TRANSGEO:103; end; theorem Th12: AFP satisfies_des & f is_Tr & g is_Tr implies f*g=g*f proof assume that A1: AFP satisfies_des and A2: f is_Tr and A3: g is_Tr; A4: g is_Dil by A3,TRANSGEO:def 11; now assume that A5: f<>id the carrier of AFP and A6: g<>id the carrier of AFP; consider a; A7: a<>f.a by A2,A5,TRANSGEO:def 11; A8: a<>g.a by A3,A6,TRANSGEO:def 11; now assume A9: LIN a,f.a,g.a; consider b such that A10: not LIN a,f.a,b by A7,AFF_1:22; consider h such that A11: h is_Tr and A12: h.a=b by A1,Th9; not LIN a,f.a,h.(g.a) proof assume LIN a,f.a,h.(g.a); then A13: LIN a,f.a,h.(g.a) & LIN a,f.a,a by AFF_1:16; A14: not LIN a,g.a,b proof assume LIN a,g.a,b; then LIN a,g.a,b & LIN a,g.a,f.a & LIN a,g.a,a by A9,AFF_1:15,16; hence contradiction by A8,A10,AFF_1:17; end; then (g*h).a=(h*g).a by A3,A11,A12,Th11; then (g*h).a=h.(g.a) by FUNCT_2:70; then A15: g.b=h.(g.a) by A12,FUNCT_2:70; a,g.a // b,g.b & a,b // g.a,g.b by A3,A4,TRANSGEO:85,100; then not LIN g.a,a,h.(g.a) by A14,A15,Lm5; hence contradiction by A7,A9,A13,AFF_1:17; end; then A16: h*g is_Tr & not LIN a,f.a,(h*g).a by A3,A11,FUNCT_2:70,TRANSGEO:105; h*(f*g)=(h*f)*g by RELAT_1:55 .=(f*h)*g by A2,A10,A11,A12,Th11 .=f*(h*g) by RELAT_1:55 .=(h*g)*f by A2,A16,Th11 .=h*(g*f) by RELAT_1:55; hence thesis by TRANSGEO:13; end; hence thesis by A2,A3,Th11; end; hence thesis by TRANSGEO:11; end; theorem Th13: f is_Tr & g is_Tr & p,f.p // p,g.p implies p,f.p // p,(f*g).p proof assume that A1: f is_Tr and A2: g is_Tr and A3: p,f.p // p,g.p; A4: f is_Dil by A1,TRANSGEO:def 11; A5: now assume g=id the carrier of AFP; then f*g=f by FUNCT_2:23; hence thesis by AFF_1:11; end; now assume g<>id the carrier of AFP; then A6: g.p<>p by A2,TRANSGEO:def 11 ; p,g.p // f.p,f.(g.p) by A4,TRANSGEO:85; then p,f.p // f.p,f.(g.p) by A3,A6,AFF_1:14; then f.p,p // f.p,f.(g.p) by AFF_1:13; then LIN f.p,p,f.(g.p) by AFF_1:def 1; then LIN p,f.p,f.(g.p) by AFF_1:15; then p,f.p // p,f.(g.p) by AFF_1:def 1; hence thesis by FUNCT_2:70; end; hence thesis by A5; end; theorem AFP satisfies_Fano & AFP satisfies_des & f is_Tr implies ex g st g is_Tr & g*g=f proof assume that A1: AFP satisfies_Fano & AFP satisfies_des and A2: f is_Tr; A3: now assume A4: f=id the carrier of AFP; set g=id the carrier of AFP; A5: g is_Tr by TRANSGEO:99; g*g=id the carrier of AFP by FUNCT_2:23; hence thesis by A4,A5; end; now assume A6: f<>id the carrier of AFP; consider a; set b=f.a; a<>b by A2,A6,TRANSGEO:def 11; then consider c such that A7: not LIN a,b,c by AFF_1:22; A8: not LIN c,a,b & not LIN c,b,a by A7,AFF_1:15; consider d such that A9: c,b // a,d & c,a // b,d by DIRAF:47; consider p such that A10: LIN b,a,p and A11: LIN c,d,p by A1,A8,A9,Th4; consider h such that A12: h is_Tr and A13: h.c = a by A1,Th9; A14: h.b=d by A8,A9,A12,A13,Th5; consider f1 being Permutation of the carrier of AFP such that A15: f1 is_Tr and A16: f1.p=a by A1,Th9; consider f2 being Permutation of the carrier of AFP such that A17: f2 is_Tr and A18: f2.p=b by A1,Th9; consider f3 being Permutation of the carrier of AFP such that A19: f3 is_Tr and A20: f3.p=c by A1,Th9; consider f4 being Permutation of the carrier of AFP such that A21: f4 is_Tr and A22: f4.p=d by A1,Th9; A23: (f2)" is_Tr by A17,TRANSGEO:104; A24: f1*f2=f4*f3 proof f1.((f3)".c)=f1.p by A20,TRANSGEO:4; then A25: (f1*(f3)").c = a by A16,FUNCT_2:70; (f3)" is_Tr by A19,TRANSGEO:104; then f1*(f3)" is_Tr by A15,TRANSGEO:105; then A26: f1*(f3)"=h by A12,A13,A25,TRANSGEO:103; f4.((f2)".b)=f4.p by A18,TRANSGEO:4; then A27: (f4*f2").b=d by A22,FUNCT_2:70; f4*f2" is_Tr by A21,A23,TRANSGEO:105; then f1*f3"=f4*f2" by A12,A14,A26,A27,TRANSGEO:103; then f1*(f3"*f3)=(f4*f2")*f3 by RELAT_1:55; then f1*(id the carrier of AFP)=(f4*f2")*f3 by FUNCT_2:88; then f1=(f4*f2")*f3 by FUNCT_2:23 .=f4*(f2"*f3) by RELAT_1:55 .=f4*(f3*f2") by A1,A19,A23,Th12 .=(f4*f3)*f2" by RELAT_1:55; then f1*f2=(f4*f3)*(f2"*f2) by RELAT_1:55 .=(f4*f3)*(id the carrier of AFP) by FUNCT_2:88 .=f4*f3 by FUNCT_2:23; hence f1*f2=f4*f3; end; A28: LIN p,c,d by A11,AFF_1:15; then A29: p,c // p,d by AFF_1:def 1; p,f3.p // p,f4.p by A20,A22,A28,AFF_1:def 1; then p,c // p,(f3*f4).p by A19,A20,A21,Th13; then A30: p,c // p,(f1*f2).p by A1,A19,A21,A24,Th12; LIN p,a,b by A10,AFF_1:15; then p,f1.p // p,f2.p by A16,A18,AFF_1:def 1; then A31: p,a // p,(f1*f2).p by A15,A16,A17,Th13; now assume p,c // p,a; then LIN p,c,a by AFF_1:def 1; then LIN p,a,c & LIN p,a,a & LIN p,a,b by A10,AFF_1:15,16; then p=a by A7,AFF_1:17; then a,c // c,b or a=d by A9,A29,AFF_1:14; then c,a // c,b or a=d by AFF_1:13; then LIN c,a,b or a=d by AFF_1:def 1; then a,c // a,b by A7,A9,AFF_1:13,15; then LIN a,c,b by AFF_1:def 1; hence contradiction by A7,AFF_1:15; end; then p=(f1*f2).p & f1*f2 is_Tr by A15,A17,A30,A31,AFF_1:14,TRANSGEO:105 ; then f1"*(f1*f2)=f1"*(id the carrier of AFP) by TRANSGEO:def 11; then (f1"*f1)*f2=f1"*(id the carrier of AFP) by RELAT_1:55; then (id the carrier of AFP)*f2=f1"*(id the carrier of AFP) by FUNCT_2:88; then f2=f1"*(id the carrier of AFP) by FUNCT_2:23; then (f2*f2).a=(f2*f1").a by FUNCT_2:23 .=f2.(f1".a) by FUNCT_2:70 .=b by A16,A18,TRANSGEO:4; then (f2*f2).a=f.a & f2*f2 is_Tr by A17,TRANSGEO:105; then f2*f2=f by A2,TRANSGEO:103; hence thesis by A17; end; hence thesis by A3; end; theorem Th15: AFP satisfies_Fano & f is_Tr & f*f=id the carrier of AFP implies f=id the carrier of AFP proof assume that A1: AFP satisfies_Fano and A2: f is_Tr and A3: f*f=id the carrier of AFP; consider a; assume f<>id the carrier of AFP; then a<>f.a by A2,TRANSGEO:def 11; then consider b such that A4: not LIN a,f.a,b by AFF_1:22; A5: f is_Dil by A2,TRANSGEO:def 11; then f.b,a // f.(f.b),f.a by TRANSGEO:85; then f.b,a // (f*f).b,f.a by FUNCT_2:70; then f.b,a // b,f.a by A3,FUNCT_1:35; then a,b // f.a,f.b & a,f.a // b,f.b & a,f.b // f.a,b by A2,A5,AFF_1:13,TRANSGEO:85,100; hence contradiction by A1,A4,Def1; end; theorem AFP satisfies_des & AFP satisfies_Fano & g is_Tr & f1 is_Tr & f2 is_Tr & g=f1*f1 & g=f2*f2 implies f1=f2 proof assume that A1: AFP satisfies_des & AFP satisfies_Fano and g is_Tr and A2: f1 is_Tr and A3: f2 is_Tr and A4: g=f1*f1 and A5: g=f2*f2; set h=f2"*f1; A6: f2" is_Tr by A3,TRANSGEO:104; then A7: h is_Tr by A2,TRANSGEO:105; h*h=f2"*(f1*(f2"*f1)) by RELAT_1:55 .=f2"*((f1*f2")*f1) by RELAT_1:55 .=f2"*((f2"*f1)*f1) by A1,A2,A6,Th12 .=f2"*(f2"*(f1*f1)) by RELAT_1:55 .=(f2"*f2")*(f1*f1) by RELAT_1:55 .=g"*g by A4,A5,FUNCT_1:66 .=id the carrier of AFP by FUNCT_2:88; then f2"*f1=id the carrier of AFP by A1,A7,Th15; then f2"*f1=f2"*f2 by FUNCT_2:88; hence f1=f2 by TRANSGEO:13; end;