Copyright (c) 1991 Association of Mizar Users
environ vocabulary ANALMETR, SYMSP_1, AFF_2, VECTSP_1, TRANSGEO, ANALOAF, DIRAF, AFF_1, INCSP_1, CONAFFM, CONMETR, PAPDESAF, RLVECT_1, ARYTM_1, FUNCT_3, RELAT_1, PARSP_1, EUCLMETR; notation SUBSET_1, STRUCT_0, REAL_1, RLVECT_1, ANALOAF, DIRAF, AFF_1, ANALMETR, GEOMTRAP, PAPDESAF, CONMETR, CONAFFM; constructors AFF_2, TRANSLAC, REAL_1, AFF_1, GEOMTRAP, CONMETR, CONAFFM, MEMBERED, XBOOLE_0; clusters ANALMETR, PAPDESAF, MEMBERED, ZFMISC_1, XBOOLE_0; requirements NUMERALS, SUBSET, ARITHM; theorems RLVECT_1, AFF_1, AFF_4, AFPROJ, ANALOAF, ANALMETR, GEOMTRAP, PAPDESAF, CONMETR, CONAFFM, AFF_2, RLSUB_2, XCMPLX_0, XCMPLX_1; begin definition let IT be OrtAfSp; attr IT is Euclidean means :Def1: for a,b,c,d being Element of the carrier of IT st a,b _|_ c,d & b,c _|_ a,d holds b,d _|_ a,c; end; definition let IT be OrtAfSp; attr IT is Pappian means :Def2: Af(IT) is Pappian; end; definition let IT be OrtAfSp; attr IT is Desarguesian means :Def3: Af(IT) is Desarguesian; end; definition let IT be OrtAfSp; attr IT is Fanoian means :Def4: Af(IT) is Fanoian; end; definition let IT be OrtAfSp; attr IT is Moufangian means :Def5: Af(IT) is Moufangian; end; definition let IT be OrtAfSp; attr IT is translation means :Def6: Af(IT) is translational; end; definition let IT be OrtAfSp; attr IT is Homogeneous means :Def7: for o,a,a1,b,b1,c,c1 being Element of IT st o,a _|_ o,a1 & o,b _|_ o,b1 & o,c _|_ o,c1 & a,b _|_ a1,b1 & a,c _|_ a1,c1 & not o,c // o,a & not o,a // o,b holds b,c _|_ b1,c1; end; reserve MS for OrtAfPl; reserve MP for OrtAfSp; theorem Th1: for a,b,c being Element of MP st not LIN a,b,c holds a<>b & b<>c & a<>c proof let a,b,c be Element of MP such that A1: not LIN a,b,c; assume A2: not thesis; reconsider b'=b,a'=a,c'=c as Element of Af(MP) by ANALMETR:47; LIN a',b',c' by A2,AFF_1:16; hence contradiction by A1,ANALMETR:55; end; theorem Th2: for a,b,c,d being Element of MS, K being Subset of the carrier of MS st a,b _|_ K & c,d _|_ K holds a,b // c,d & a,b // d,c proof let a,b,c,d be Element of MS, K be Subset of the carrier of MS such that A1: a,b _|_ K & c,d _|_ K; reconsider K'=K as Subset of Af(MS) by ANALMETR:57; K is_line by A1,ANALMETR:62; then K' is_line by ANALMETR:58; then consider p',q' being Element of Af(MS) such that A2: p' in K' & q' in K' and A3: p' <> q' by AFF_1:31; reconsider p=p',q=q' as Element of MS by ANALMETR:47; a,b _|_ p,q & c,d _|_ p,q by A1,A2,ANALMETR:75; hence a,b // c,d by A3,ANALMETR:85; hence a,b // d,c by ANALMETR:81; end; theorem for a,b being Element of MS, A,K being Subset of the carrier of MS st a<>b & (a,b _|_ K or b,a _|_ K) & (a,b _|_ A or b,a _|_ A) holds K // A proof let a,b be Element of MS, A,K be Subset of MS such that A1: a<>b and A2: a,b _|_ K or b,a _|_ K and A3: a,b _|_ A or b,a _|_ A; A4: a,b _|_ K & a,b _|_ A by A2,A3,ANALMETR:67; then consider p,q being Element of MS such that A5: p<>q & K = Line(p,q) & a,b _|_ p,q by ANALMETR:def 14; consider r,s being Element of MS such that A6: r<>s & A = Line(r,s) & a,b _|_ r,s by A4,ANALMETR:def 14; p,q // r,s by A1,A5,A6,ANALMETR:85; hence thesis by A5,A6,ANALMETR:def 16; end; theorem Th4: for x,y,z being Element of MP st LIN x,y,z holds LIN x,z,y & LIN y,x,z & LIN y,z,x & LIN z,x,y & LIN z,y,x proof let x,y,z be Element of MP such that A1: LIN x,y,z; reconsider x'=x,y'=y,z'=z as Element of Af(MP) by ANALMETR:47; LIN x',y',z' by A1,ANALMETR:55; then LIN x',z',y' & LIN y',x',z' & LIN y',z',x' & LIN z',x',y' & LIN z',y',x' by AFF_1:15; hence thesis by ANALMETR:55; end; theorem Th5: for a,b,c being Element of MS st not LIN a,b,c ex d being Element of MS st d,a _|_ b,c & d,b _|_ a,c proof let a,b,c be Element of MS; assume A1: not LIN a,b,c; then A2: a<>c & b<>c by Th1; set A=Line(a,c),K=Line(b,c); A3: A is_line & K is_line by A2,ANALMETR:def 13; then consider P being Subset of MS such that A4: b in P & A _|_ P by CONMETR:3; consider Q being Subset of MS such that A5: a in Q & K _|_ Q by A3,CONMETR:3; reconsider P'=P,Q'=Q as Subset of Af(MS) by ANALMETR:57; P is_line & Q is_line by A4,A5,ANALMETR:62; then A6: P' is_line & Q' is_line by ANALMETR:58; reconsider A'=A,K'=K as Subset of Af(MS) by ANALMETR:57; reconsider a'=a,b'=b,c'=c as Element of Af(MS) by ANALMETR:47; A7: A'=Line(a',c') & K'=Line(b',c') by ANALMETR:56; then A8: a' in A' & c' in A' & b' in K' & c' in K' by AFF_1:26; not P' // Q' proof assume not thesis; then P // Q by ANALMETR:64; then A _|_ Q by A4,ANALMETR:73; then A // K by A5,ANALMETR:87; then A' // K' by ANALMETR:64; then b' in A' by A8,AFF_1:59; then LIN a',c',b' by A7,AFF_1:def 2; then LIN a',b',c' by AFF_1:15; hence contradiction by A1,ANALMETR:55; end; then consider d' being Element of Af(MS) such that A9: d' in P' & d' in Q' by A6,AFF_1:72; reconsider d=d' as Element of the carrier of MS by ANALMETR:47; take d; thus thesis by A4,A5,A8,A9,ANALMETR:78; end; theorem Th6: for a,b,c,d1,d2 being Element of MS st not LIN a,b,c & d1,a _|_ b,c & d1,b _|_ a,c & d2,a _|_ b,c & d2,b _|_ a,c holds d1=d2 proof let a,b,c,d1,d2 be Element of MS such that A1: not LIN a,b,c and A2: d1,a _|_ b,c & d1,b _|_ a,c and A3: d2,a _|_ b,c & d2,b _|_ a,c; assume A4: d1<>d2; A5: a<>c & b<>a & b<>c by A1,Th1; then A6: d1,a // d2,a & d1,b // d2,b by A2,A3,ANALMETR:85; reconsider a'=a,b'=b,c'=c,d1'=d1,d2'=d2 as Element of Af(MS) by ANALMETR:47; d1',a' // d2',a' & d1',b' // d2',b' by A6,ANALMETR:48; then a',d1' // a',d2' & b',d1' // b',d2' by AFF_1:13; then LIN a',d1',d2' & LIN b',d1',d2' by AFF_1:def 1; then A7: LIN d1',d2',a' & LIN d1',d2',b' by AFF_1:15; LIN d1',d2',d1' & LIN d1',d2',d2' by AFF_1:16; then A8: LIN a',b',d1' & LIN a',b',d2' by A4,A7,AFF_1 :17; set X'=Line(a',b'); A9: X' is_line & a' in X' & b' in X' by A5,AFF_1:26,def 3; reconsider X=X' as Subset of MS by ANALMETR:57; A10: d1 in X & d2 in X & a in X & b in X & X is_line by A5,A8,A9,AFF_1:39,ANALMETR:58; (a<>d1 or a<>d2) & (b<>d1 or b<>d2) by A4; then a,c _|_ X & b,c _|_ X by A2,A3,A10,ANALMETR:77; then a,c // b,c by Th2; then a',c' // b',c' by ANALMETR:48; then c',b' // c',a' by AFF_1:13; then LIN c',b',a' by AFF_1:def 1; then LIN a',b',c' by AFF_1:15; hence contradiction by A1,ANALMETR:55; end; theorem Th7: for a,b,c,d being Element of MS st a,b _|_ c,d & b,c _|_ a,d & LIN a,b,c holds (a=c or a=b or b=c) proof let a,b,c,d be Element of MS such that A1: a,b _|_ c,d & b,c _|_ a,d and A2: LIN a,b,c; assume A3: not thesis; reconsider a'=a,b'=b,c'=c,d'=d as Element of Af(MS) by ANALMETR:47; A4: LIN a',b',c' by A2,ANALMETR:55; LIN c,b,a by A2,Th4; then a,b // a,c & c,b // c,a by A2,ANALMETR:def 11; then a,b // a,c & a,c // b,c by ANALMETR:81; then a,c _|_ c,d & a,c _|_ a,d by A1,A3,ANALMETR:84; then c,d // a,d by A3,ANALMETR:85; then d,c // d,a by ANALMETR:81; then LIN d,c,a by ANALMETR:def 11; then LIN a,c,d by Th4; then A5: LIN a',c',d' by ANALMETR:55; consider A' being Subset of the carrier of Af(MS) such that A6: A' is_line and A7: a' in A' & b' in A' & c' in A' by A4, AFF_1:33; reconsider A=A' as Subset of MS by ANALMETR:57; A8: A is_line by A6,ANALMETR:58; A9: a in A & b in A & c in A & d in A by A3,A5,A6,A7,AFF_1:39; c,d _|_ A & a,d _|_ A by A1,A3,A7,A8,ANALMETR:77; then c =d & a=d by A9, ANALMETR:71; hence contradiction by A3; end; theorem Th8: MS is Euclidean iff 3H_holds_in MS proof A1: now assume A2: 3H_holds_in MS; now let a,b,c,d be Element of MS such that A3: a,b _|_ c,d & b,c _|_ a,d; A4: now assume A5: not LIN a,b,c; then consider d1 being Element of the carrier of MS such that A6: d1,a _|_ b,c & d1,b _|_ a,c & d1,c _|_ a,b by A2,CONAFFM:def 3; A7: d,a _|_ c,b & d,c _|_ a,b by A3,ANALMETR:83; A8: d1,a _|_ c,b & d1,c _|_ a,b by A6,ANALMETR:83; not LIN a,c,b by A5,Th4; then d,b _|_ a,c by A6,A7,A8,Th6; hence b,d _|_ a,c by ANALMETR:83; end; now assume A9: LIN a,b,c; A10: a=c implies b,d _|_ a,c by ANALMETR:80; A11: a=b implies b,d _|_ a,c by A3,ANALMETR:83; b=c implies b,d _|_ a,c by A3,ANALMETR:83; hence b,d _|_ a,c by A3,A9,A10,A11,Th7; end; hence b,d _|_ a,c by A4; end; hence MS is Euclidean by Def1; end; now assume A12: MS is Euclidean; now let a,b,c be Element of MS; assume not LIN a,b,c; then consider d being Element of MS such that A13: d,a _|_ b,c & d,b _|_ a,c by Th5; take d; b,c _|_ a,d & c,a _|_ b,d by A13,ANALMETR:83; then c,d _|_ b,a by A12,Def1; hence d,a _|_ b,c & d,b _|_ a,c & d,c _|_ a,b by A13,ANALMETR:83; end; hence 3H_holds_in MS by CONAFFM:def 3; end; hence thesis by A1; end; theorem Th9: MS is Homogeneous iff ODES_holds_in MS proof ODES_holds_in MS iff for o,a,a1,b,b1,c,c1 being Element of MS st o,a _|_ o,a1 & o,b _|_ o,b1 & o,c _|_ o,c1 & a,b _|_ a1,b1 & a,c _|_ a1,c1 & not o,c // o,a & not o,a // o,b holds b,c _|_ b1,c1 by CONAFFM:def 4; hence thesis by Def7; end; Lm1: PAP_holds_in MS iff Af(MS) satisfies_PAP' proof set AS=Af(MS); A1: now assume A2: PAP_holds_in MS; now let M,N be Subset of AS, o,a,b,c,a',b',c' be Element of the carrier of AS such that A3: M is_line & N is_line and A4: M<>N and A5: o in M & o in N and A6: o<>a & o<>a' & o<>b & o<>b' & o<>c & o<>c' and A7: a in M & b in M & c in M & a' in N & b' in N & c' in N and A8: a,b' // b,a' & b,c' // c,b'; reconsider M'=M,N'=N as Subset of MS by ANALMETR:57; A9: M' is_line & N' is_line by A3,ANALMETR:58; reconsider a1=a,b1=b,c1=c,a1'=a',b1'=b',c1'=c' as Element of the carrier of MS by ANALMETR:47; A10: not a1' in M' & not b1 in N' by A4,A5,A6,A7,A9,CONMETR:5; a1,b1' // b1,a1' & b1,c1' // c1,b1' by A8,ANALMETR:48; then b1,a1' // a1,b1' & b1,c1' // c1,b1' by ANALMETR:81; then c1,a1' // a1,c1' by A2,A5,A6,A7,A9,A10,CONMETR:def 2; then a1,c1' // c1,a1' by ANALMETR:81; hence a,c' // c,a' by ANALMETR:48; end ; hence Af(MS) satisfies_PAP' by AFF_2:def 2; end; now assume A11: Af(MS) satisfies_PAP'; now let o,a1,a2,a3,b1,b2,b3 be Element of MS, M,N be Subset of the carrier of MS such that A12: M is_line & N is_line and A13: o in M & a1 in M & a2 in M & a3 in M & o in N & b1 in N & b2 in N & b3 in N and A14: not b2 in M & not a3 in N and A15: o<>a1 & o<>a2 & o<>a3 & o<>b1 & o<>b2 & o<>b3 and A16: a3,b2 // a2,b1 & a3,b3 // a1,b1; A17: a2,b1 // a3,b2 & a3,b3 // a1,b1 by A16,ANALMETR:81; reconsider M'=M,N'=N as Subset of AS by ANALMETR:57; A18: M' is_line & N' is_line by A12,ANALMETR:58; reconsider a=a1,b=a2,c = a3,a'=b1,b'=b2,c'=b3 as Element of the carrier of AS by ANALMETR:47; b,a' // c,b' & c,c' // a,a' by A17,ANALMETR:48; then b,c' // a,b' by A11,A13,A14,A15,A18,AFF_2:def 2; then a2,b3 // a1,b2 by ANALMETR:48; hence a1,b2 // a2,b3 by ANALMETR:81; end; hence PAP_holds_in MS by CONMETR:def 2; end; hence thesis by A1; end; theorem Th10: MS is Pappian iff PAP_holds_in MS proof set AS=Af(MS); A1: now assume MS is Pappian; then AS satisfies_PAP' by Def2; hence PAP_holds_in MS by Lm1;end; now assume PAP_holds_in MS; then AS is Pappian by Lm1; hence MS is Pappian by Def2; end; hence thesis by A1; end; Lm2: DES_holds_in MS iff Af(MS) satisfies_DES' proof set AS=Af(MS); A1: now assume A2: DES_holds_in MS; now let A,P,C be Subset of AS, o,a,b,c,a',b',c' be Element of the carrier of AS such that A3: o in A & o in P & o in C and A4: o<>a & o<>b & o<>c and A5: a in A & a' in A & b in P & b' in P & c in C & c' in C and A6: A is_line & P is_line & C is_line and A7: A<>P & A<>C and A8: a,b // a',b' & a,c // a',c'; now assume A9: o<>a' & a<>a'; then A10: b<>b' & c <>c' by A3,A4,A5,A6,A7,A8,AFF_4:9; A11: now assume LIN b,b',a; then a in P by A5,A6,A10,AFF_1:39; hence contradiction by A3,A4,A5,A6,A7,AFF_1:30; end; A12: now assume LIN a,a',c; then c in A by A5,A6,A9,AFF_1:39; hence contradiction by A3,A4,A5,A6,A7,AFF_1:30; end; reconsider o1=o,a1=a,b1=b,c1=c,a1'=a',b1'=b',c1'=c' as Element of the carrier of MS by ANALMETR:47; A13: o1<>a1 & o1<>b1 & o1<>c1 & o1<>a1' & o1<>b1' & o1<>c1' by A3,A4,A5,A6,A7, A8,A9,AFF_4:8; LIN o,a,a' & LIN o,b,b' & LIN o,c,c' by A3,A5,A6,AFF_1:33; then A14: LIN o1,a1,a1' & LIN o1,b1,b1' & LIN o1,c1,c1' by ANALMETR:55; A15: a1,b1 // a1',b1' & a1,c1 // a1',c1' by A8,ANALMETR:48; A16: not LIN b1,b1',a1 by A11,ANALMETR:55; not LIN a1,a1',c1 by A12,ANALMETR:55; then b1,c1 // b1',c1' by A2,A13,A14,A15,A16,CONAFFM:def 1; hence b,c // b',c' by ANALMETR:48; end; hence b,c // b',c' by A3,A4,A5,A6,A7,A8,AFPROJ:50; end; hence AS satisfies_DES' by AFF_2:def 4; end; now assume A17: AS satisfies_DES'; now let o,a,a1,b,b1,c,c1 be Element of MS such that A18: o<>a & o<>a1 & o<>b & o<>b1 & o<>c & o<>c1 and A19: not LIN b,b1,a & not LIN a,a1,c and A20: LIN o,a,a1 & LIN o,b,b1 & LIN o,c,c1 and A21: a,b // a1,b1 & a,c // a1,c1; reconsider o'=o,a'=a,b'=b,c'=c,a1'=a1,b1'=b1, c1'=c1 as Element of AS by ANALMETR:47; A22: a',b' // a1',b1' & a',c' // a1',c1' by A21,ANALMETR:48; A23: LIN o',a',a1' & LIN o',b',b1' & LIN o',c',c1' by A20,ANALMETR:55; then consider A being Subset of AS such that A24: A is_line and A25: o' in A & a' in A & a1' in A by AFF_1:33; consider P being Subset of AS such that A26: P is_line and A27: o' in P & b' in P & b1' in P by A23,AFF_1:33; consider C being Subset of AS such that A28: C is_line and A29: o' in C & c' in C & c1' in C by A23,AFF_1:33; A30: A<>P proof assume A=P; then LIN b',b1',a' by A25,A26,A27,AFF_1:33 ; hence contradiction by A19,ANALMETR:55; end; A<>C proof assume A=C; then LIN a',a1',c' by A24,A25,A29,AFF_1:33 ; hence contradiction by A19,ANALMETR:55; end; then b',c' // b1',c1' by A17,A18,A22,A24,A25,A26,A27,A28,A29,A30,AFF_2:def 4 ; hence b,c // b1,c1 by ANALMETR:48; end; hence DES_holds_in MS by CONAFFM:def 1; end ; hence thesis by A1; end; theorem Th11: MS is Desarguesian iff DES_holds_in MS proof set AS=Af(MS); A1: now assume MS is Desarguesian; then AS satisfies_DES' by Def3; hence DES_holds_in MS by Lm2; end; now assume DES_holds_in MS; then AS is Desarguesian by Lm2; hence MS is Desarguesian by Def3; end; hence thesis by A1; end; theorem MS is Moufangian iff TDES_holds_in MS proof set AS=Af(MS); A1: now assume A2: TDES_holds_in MS; now let K be Subset of AS, o,a,b,c,a',b',c' be Element of the carrier of AS such that A3: K is_line and A4: o in K & c in K & c' in K and A5: not a in K and A6: o<>c & a<>b and A7: LIN o,a,a' & LIN o,b,b' and A8: a,b // a',b' & a,c // a',c' and A9: a,b // K; reconsider o1=o,a1=a,b1=b,c1=c,a1'=a',b1'=b',c1'=c' as Element of the carrier of MS by ANALMETR:47; A10: LIN o,c,c' by A3,A4,AFF_1:33; then A11: LIN o1,a1,a1' & LIN o1,b1,b1' & LIN o1,c1,c1' by A7,ANALMETR:55; A12: o1<>c1 & o1<>a1 & o1<>b1 by A4,A5,A6,A9,AFF_1:49; A13: b1,a1 // b1',a1' proof a1,b1 // a1',b1' by A8,ANALMETR:48; hence thesis by ANALMETR:81; end; A14: b1,a1 // o1,c1 proof a,b // o,c by A3,A4,A6,A9,AFF_1:41; then b,a // o,c by AFF_1:13; hence thesis by ANALMETR:48; end; A15: a1,c1 // a1',c1' by A8,ANALMETR:48; A16: not LIN o,a,c proof assume not thesis; then LIN o,c,a by AFF_1:15; hence contradiction by A3,A4,A5,A6,AFF_1:39; end; A17: not LIN o,a,b proof assume not thesis; then A18: LIN a,b,o by AFF_1:15; set M=Line(a,b); A19: a in M & o in M by A18,AFF_1:26,def 2; M // K by A6,A9,AFF_1:def 5; then a in K by A4,A19,AFF_1:59; hence contradiction by A3,A4,A16,AFF_1:33; end; A20: now assume A21: a'=o; then A22: b'=o by A7,A8,A17,AFF_1:69; c'=o by A7,A8,A10,A16,A21,AFF_1:69; hence b,c // b',c' by A22,AFF_1:12; end; now assume A23: a'<>o; A24: now assume a=a'; then A25: a,b // a',b & a,c // a',c & LIN o,b,b & LIN o,c,c by AFF_1:11,16; then A26: b=b' by A7,A8,A17,AFF_1:70; c =c' by A7,A8,A10,A16,A25,AFF_1:70; hence b,c // b',c' by A26,AFF_1:11; end; now assume A27: a<>a'; A28: o1<>a1' & o1<>b1' & o1<>c1' proof thus o1<>a1' by A23; A29: b,a // b',a' & c,a // c',a' by A8,AFF_1:13; not LIN o,b,a & not LIN o,c,a by A16,A17,AFF_1:15; hence o1<>b1' & o1<>c1' by A7,A10,A23,A29,AFF_1:69; end; A30: not LIN a1,a1',c1 proof assume not thesis; then A31: LIN a,a',c by ANALMETR:55; LIN a,a',o & LIN a,a',a by A7,AFF_1:15,16; hence contradiction by A16,A27,A31,AFF_1:17; end; not LIN a1,a1',b1 proof assume not thesis; then A32: LIN a,a',b by ANALMETR:55; LIN a,a',o & LIN a,a',a by A7,AFF_1:15,16; hence contradiction by A17,A27,A32,AFF_1:17; end; then b1,c1 // b1',c1' by A2,A11,A12,A13,A14,A15,A28,A30,CONMETR:def 5; hence b,c // b',c' by ANALMETR:48; end; hence b,c // b',c' by A24; end; hence b,c // b',c' by A20; end; then AS is Moufangian by AFF_2:def 7; hence MS is Moufangian by Def5; end; now assume MS is Moufangian; then A33: AS satisfies_TDES' by Def5; now let o,a,a1,b,b1,c,c1 be Element of MS such that A34: o<>a & o<>a1 & o<>b & o<>b1 & o<>c & o<>c1 and A35: not LIN b,b1,a & not LIN b,b1,c and A36: LIN o,a,a1 & LIN o,b,b1 & LIN o,c,c1 and A37: a,b // a1,b1 & a,b // o,c & b,c // b1,c1; reconsider o'=o,a'=a,a1'=a1,b'=b,b1'=b1,c'=c,c1'=c1 as Element of the carrier of AS by ANALMETR:47; set K=Line(o',c'); A38: K is_line & o' in K & c' in K by A34,AFF_1:26,def 3; LIN o',c',c1' by A36,ANALMETR:55; then A39: c1' in K & o'<>c' by A34,A38,AFF_1:39 ; A40: LIN o',a',a1' & LIN o',b',b1' by A36,ANALMETR:55; A41: not b' in K proof assume A42: b' in K; then b1' in K by A34,A38,A40,AFF_1:39 ; then LIN b',b1',c' by A38,A42,AFF_1:33; hence contradiction by A35,ANALMETR:55;end; A43: b',a' // K proof a',b' // o',c' by A37,ANALMETR:48; then a',b' // K by A34,AFF_1:def 4; hence thesis by AFF_1:48; end; A44: b',a' // b1',a1' proof a',b' // a1',b1' by A37,ANALMETR:48; hence thesis by AFF_1:13; end; A45: b',c' // b1',c1' by A37,ANALMETR:48; b'<>a' by A35,Th1; then a',c' // a1',c1' by A33,A38,A39,A40,A41,A43,A44,A45,AFF_2:def 7; hence a,c // a1,c1 by ANALMETR:48; end; hence TDES_holds_in MS by CONMETR:def 5; end; hence thesis by A1; end; Lm3: des_holds_in MS iff Af(MS) satisfies_des' proof set AS=Af(MS); A1: now assume A2: des_holds_in MS; now let A,P,C be Subset of the carrier of AS, a,b,c,a',b',c' be Element of AS such that A3: A // P & A // C and A4: a in A & a' in A & b in P & b' in P & c in C & c' in C and A5: A is_line & P is_line & C is_line and A6: A<>P & A<>C and A7: a,b // a',b' & a,c // a',c'; A8: not a in P & not a in C by A3,A4,A6,AFF_1:59; A9: now assume a=a'; then LIN a,b,b' & LIN a,c,c' by A7,AFF_1:def 1; then LIN b,b',a & LIN c,c',a by AFF_1:15; then b = b' & c = c' by A4,A5,A8,AFF_1:39;hence b,c // b',c' by AFF_1:11;end; now assume A10: a<>a'; reconsider aa=a,a1=a',bb=b,b1=b',cc=c,c1=c' as Element of MS by ANALMETR:47; A11: not LIN aa,a1,bb proof assume not thesis; then LIN a,a',b by ANALMETR:55; then b in A by A4,A5,A10,AFF_1:39;hence contradiction by A3,A4,A6,AFF_1:59 ;end; A12: not LIN aa,a1,cc proof assume not thesis; then LIN a,a',c by ANALMETR:55; then c in A by A4,A5,A10,AFF_1:39;hence contradiction by A3,A4,A6,AFF_1:59 ;end; A13: aa,a1 // bb,b1 & aa,a1 // cc,c1 proof a,a' // b,b' & a,a' // c,c' by A3,A4,AFF_1:53; hence aa,a1 // bb,b1 & aa,a1 // cc,c1 by ANALMETR:48; end ; aa,bb // a1,b1 & aa,cc // a1,c1 by A7,ANALMETR:48; then bb,cc // b1,c1 by A2,A11,A12,A13,CONMETR:def 8; hence b,c // b',c' by ANALMETR:48; end; hence b,c // b',c' by A9; end; hence AS satisfies_des' by AFF_2:def 11; end; now assume A14: AS satisfies_des'; now let a,a1,b,b1,c,c1 be Element of the carrier of MS such that A15: not LIN a,a1,b & not LIN a,a1,c and A16: a,a1 // b,b1 & a,a1 // c,c1 and A17: a,b // a1,b1 & a,c // a1,c1; reconsider a'=a,a1'=a1,b'=b,b1'=b1,c'=c,c1'=c1 as Element of AS by ANALMETR:47; A18: not a',a1' // a',b' & not a',a1' // a',c' proof assume not thesis; then a,a1 // a,b or a,a1 // a,c by ANALMETR:48;hence contradiction by A15, ANALMETR:def 11; end; A19: a',a1' // b',b1' & a',a1' // c',c1' by A16,ANALMETR:48; A20: a',b' // a1',b1' & a',c' // a1',c1' by A17,ANALMETR:48; A21: a'<>a1' by A18,AFF_1:12; set A=Line(a',a1'); A22: A is_line & a' in A & a1' in A by A21,AFF_1:26,def 3; then A23: a',a1' // A by AFF_1:37; consider P being Subset of AS such that A24: b' in P and A25: A // P by A22,AFF_1:63; consider C being Subset of AS such that A26: c' in C and A27: A // C by A22,AFF_1:63; A28: P is_line & C is_line by A25,A27,AFF_1:50; a',a1' // P & a',a1' // C by A23,A25,A27,AFF_1:57; then b',b1' // P & c',c1' // C by A19,A21,AFF_1:46; then A29: b1' in P & c1' in C by A24,A26,A28,AFF_1:37; A30: A<>P by A18,A22,A24,AFF_1:65; A<>C by A18,A22,A26,AFF_1:65; then b',c' // b1',c1' by A14,A20,A22,A24,A25,A26,A27,A28,A29,A30,AFF_2:def 11 ; hence b,c // b1,c1 by ANALMETR:48; end; hence des_holds_in MS by CONMETR:def 8; end; hence thesis by A1; end; theorem MS is translation iff des_holds_in MS proof set AS=Af(MS); A1: now assume MS is translation; then AS satisfies_des' by Def6; hence des_holds_in MS by Lm3; end; now assume des_holds_in MS; then AS is translational by Lm3; hence MS is translation by Def6; end; hence thesis by A1; end; theorem Th14: MS is Homogeneous implies MS is Desarguesian proof assume MS is Homogeneous; then ODES_holds_in MS by Th9; then DES_holds_in MS by CONAFFM:1; hence thesis by Th11; end; theorem Th15: MS is Euclidean Desarguesian implies MS is Pappian proof assume MS is Euclidean Desarguesian; then 3H_holds_in MS & DES_holds_in MS by Th8,Th11; then OPAP_holds_in MS & DES_holds_in MS by CONMETR:15; then PAP_holds_in MS by CONMETR:13; hence thesis by Th10; end; reserve V for RealLinearSpace; reserve w,y,u,v for VECTOR of V; theorem Th16: for o,c,c1,a,a1,a2 being Element of MS st not LIN o,c,a & o<>c1 & o,c _|_ o,c1 & o,a _|_ o,a1 & o,a _|_ o,a2 & c,a _|_ c1,a1 & c,a _|_ c1,a2 holds a1=a2 proof let o,c,c1,a,a1,a2 be Element of MS such that A1: not LIN o,c,a & o<>c1 and A2: o,c _|_ o,c1 and A3: o,a _|_ o,a1 & o,a _|_ o,a2 and A4: c,a _|_ c1,a1 & c,a _|_ c1,a2; assume A5: a1<>a2; a<>c & o<>a & o<>c by A1,Th1; then A6: o,a1 // o,a2 & c1,a1 // c1,a2 by A3,A4,ANALMETR:85; reconsider o'=o,a1'=a1,a2'=a2,c1'=c1 as Element of Af(MS) by ANALMETR:47; o',a1' // o',a2' & c1',a1' // c1',a2' by A6,ANALMETR:48; then LIN o',a1',a2' & LIN c1',a1',a2' by AFF_1:def 1; then A7:LIN a1',a2',o' & LIN a1',a2',c1' by AFF_1:15; LIN a1',a2',a1' & LIN a1',a2',a2' by AFF_1:16; then LIN o',c1',a1' & LIN o',c1',a2' by A5,A7,AFF_1:17; then o',c1' // o',a1' & o',c1' // o',a2' by AFF_1:def 1; then o,c1 // o,a1 & o,c1 // o,a2 by ANALMETR:48; then A8: o,c _|_ o,a1 & o,c _|_ o,a2 by A1,A2,ANALMETR:84; o<>a1 or o<>a2 by A5; then o,c // o,a by A3,A8,ANALMETR: 85; hence contradiction by A1,ANALMETR:def 11; end; theorem for o,c,c1,a being Element of MS st not LIN o,c,a & o<>c1 ex a1 being Element of MS st o,a _|_ o,a1 & c,a _|_ c1,a1 proof let o,c,c1,a be Element of MS such that A1: not LIN o,c,a & o<>c1; set X=Line(c,a),Y=Line(o,a); c <>a & o<>a by A1,Th1; then A2: X is_line & Y is_line by ANALMETR:def 13; then consider X' being Subset of MS such that A3: c1 in X' & X _|_ X' by CONMETR:3; consider Y' being Subset of MS such that A4: o in Y' & Y _|_ Y' by A2,CONMETR:3; A5: X' is_line & Y' is_line by A3,A4,ANALMETR:62; reconsider o'=o,c'=c,a'=a as Element of Af(MS) by ANALMETR:47; X=Line(c',a') & Y=Line(o',a') by ANALMETR:56; then A6: c in X & a in X & o in Y & a in Y by AFF_1:26; A7: not X' // Y' proof assume not thesis; then X' _|_ Y by A4,ANALMETR:73; then A8: X // Y by A3,ANALMETR:87; reconsider X1=X,Y1=Y as Subset of the carrier of Af(MS) by ANALMETR:57; X1 // Y1 by A8,ANALMETR:64; then o in X & a in X & c in X by A6,AFF_1:59; hence contradiction by A1,A2,CONMETR:4; end; reconsider X1=X',Y1=Y' as Subset of Af(MS) by ANALMETR:57; A9: X1 is_line & Y1 is_line by A5,ANALMETR:58; not X1 // Y1 by A7,ANALMETR:64; then consider a1' being Element of the carrier of Af(MS) such that A10: a1' in X1 & a1' in Y1 by A9,AFF_1:72; reconsider a1=a1' as Element of MS by ANALMETR:47; take a1; thus thesis by A3,A4,A6,A10,ANALMETR:78; end; Lm4: for u,v,y being VECTOR of V holds (u-y)-(v-y)=u-v & (u+y)-(v+y) = u-v proof let u,v,y be VECTOR of V; thus (u-y)-(v-y) = (u-y)+(y-v) by ANALOAF:6 .= u-v by ANALOAF:4; thus (u+y)-(v+y) = (u+ -(-y))-(v+y) by RLVECT_1:30 .= (u-(-y))-(v+y) by RLVECT_1:def 11 .= (u-(-y))-(v + -(-y)) by RLVECT_1:30 .= (u-(-y))-(v-(-y)) by RLVECT_1:def 11 .= (u-(-y))+((-y)-v) by ANALOAF:6 .= u-v by ANALOAF:4; end; Lm5: Gen w,y implies for a,b,c being Real holds (PProJ(w,y,a*w+b*y,(c*b)*w+(-c*a)*y) = 0 & a*w+b*y,(c*b)*w+(-c*a)*y are_Ort_wrt w,y) proof assume A1: Gen w,y; let a,b,c be Real; pr1(w,y,a*w+b*y)=a & pr1(w,y,(c*b)*w+(-c*a)*y) = c*b & pr2(w,y,a*w+b*y)=b & pr2(w,y,(c*b)*w+(-c*a)*y) = -c*a by A1,GEOMTRAP:def 4,def 5; hence PProJ (w,y,a*w+b*y,(c*b)*w+(-c*a)*y) = a*(b*c)+b*(-c*a) by GEOMTRAP:def 6 .= a*(b*c) + -(b*(c*a)) by XCMPLX_1:175 .= a*(b*c) + -(a*(b*c)) by XCMPLX_1:4 .= 0 by XCMPLX_0:def 6; hence a*w+b*y,(c*b)*w+(-c*a)*y are_Ort_wrt w,y by A1,GEOMTRAP:34; end; theorem Th18: for a,b being Real st Gen w,y & 0.V<>u & 0.V<>v & u,v are_Ort_wrt w,y & u=a*w+b*y ex c being Real st c <>0 & v=(c*b)*w+(-c*a)*y proof let a,b be Real such that A1: Gen w,y and A2: 0.V<>u & 0.V<>v and A3: u,v are_Ort_wrt w,y and A4: u=a*w+b*y; set v'=b*w+(-a)*y; v'= (1*b)*w+(-1*a)*y; then u,v' are_Ort_wrt w,y by A1,A4,Lm5; then consider a1,b1 being Real such that A5: a1*v = b1*v' and A6: a1<>0 or b1<>0 by A1,A2,A3,ANALMETR:13; A7: now assume A8: b1=0; then 0.V = a1*v by A5,RLVECT_1:23; hence contradiction by A2,A6,A8,RLVECT_1:24; end; A9: now assume A10: a1=0; then 0.V = b1*v' by A5,RLVECT_1:23; then v'=0.V by A6,A10,RLVECT_1:24 ; then b=0 & -a=0 by A1,ANALMETR:def 1; then u=0*w+0*y by A4,XCMPLX_1:135 .= 0.V + 0*y by RLVECT_1:23 .= 0.V + 0.V by RLVECT_1:23 .= 0.V by RLVECT_1:10; hence contradiction by A2; end; take c =a1"*b1; now assume c =0; then a1"=0 by A7,XCMPLX_1:6; hence contradiction by A9,XCMPLX_1:203; end; hence c <>0; thus v=(a1")*(b1*v') by A5,A9,ANALOAF:12 .= c*v' by RLVECT_1:def 9 .= c*(b*w) + c*((-a)*y) by RLVECT_1:def 9 .= (c*b)*w + c*((-a)*y) by RLVECT_1:def 9 .= (c*b)*w + (c*(-a))*y by RLVECT_1:def 9 .= (c*b)*w + (-c*a)*y by XCMPLX_1:175; end; theorem Th19: Gen w,y & 0.V<>u & 0.V<>v & u,v are_Ort_wrt w,y implies ex c being Real st for a,b being Real holds a*w+b*y,(c*b)*w+(-c*a)*y are_Ort_wrt w,y & (a*w+b*y)-u,((c*b)*w+(-c*a)*y)-v are_Ort_wrt w,y proof assume that A1: Gen w,y and A2: 0.V<>u & 0.V<>v and A3: u,v are_Ort_wrt w,y; consider a1,a2 being Real such that A4: u=a1*w+a2*y by A1,ANALMETR:def 1; consider c being Real such that c <>0 and A5: v=(c*a2)*w+(-c*a1)*y by A1,A2,A3,A4,Th18; take c; let a,b be Real; set u'=a*w+b*y,v'=(c*b)*w+(-c*a)*y; thus a*w+b*y,(c*b)*w+(-c*a)*y are_Ort_wrt w,y by A1,Lm5; A6: pr1(w,y,u')=a & pr1(w,y,v') = c*b & pr2(w,y,u')=b & pr2(w,y,v') = -c*a by A1,GEOMTRAP:def 4,def 5; A7: pr1(w,y,u)=a1 & pr1(w,y,v)=c*a2 & pr2(w,y,u)=a2 & pr2(w,y,v)=-c*a1 by A1,A4,A5,GEOMTRAP:def 4,def 5; A8: PProJ(w,y,(a*w+b*y)-u,((c*b)*w+(-c*a)*y)-v) = PProJ(w,y,u'-u,v')-PProJ(w,y,u'-u,v) by A1,GEOMTRAP:32 .= (PProJ(w,y,u',v')-PProJ(w,y,u,v')) - PProJ(w,y,u'-u,v) by A1,GEOMTRAP:32 .= (0 - PProJ(w,y,u,v')) - PProJ(w,y,u'-u,v) by A1,Lm5 .= (-PProJ(w,y,u,v')) - PProJ(w,y,u'-u,v) by XCMPLX_1:150 .= (-PProJ(w,y,u,v')) - (PProJ(w,y,u',v) - PProJ(w,y,u,v)) by A1,GEOMTRAP:32 .= (-PProJ(w,y,u,v')) - (PProJ(w,y,u',v) - 0) by A1,A3,GEOMTRAP:34 .= (-1*PProJ(w,y,u,v')) - PProJ(w,y,u',v) .= (-1)*PProJ(w,y,u,v') - PProJ(w,y,u',v) by XCMPLX_1:175 .= (-1)*PProJ(w,y,u,v') + -1*PProJ(w,y,u',v) by XCMPLX_0:def 8 .= (-1)*PProJ(w,y,u,v') + (-1)*PProJ(w,y,u',v) by XCMPLX_1:175 .= (-1)*(PProJ(w,y,u,v') + PProJ(w,y,u',v)) by XCMPLX_1:8; A9: PProJ(w,y,u,v') = a1*(c*b)+a2*(-c*a) by A6,A7,GEOMTRAP:def 6; PProJ(w,y,u',v) = (c*a2)*a+(-c*a1)*b by A6,A7,GEOMTRAP:def 6; then PProJ(w,y,u,v') + PProJ(w,y,u',v) = a1*(c*b) + (a2*(-c*a) + ((c*a2)*a+(-c*a1)*b)) by A9,XCMPLX_1:1 .= a1*(c*b) + ((a2*(-c*a) + (c*a2)*a)+(-c*a1)*b) by XCMPLX_1:1 .= a1*(c*b) + ((a2*((-c)*a) + (c*a2)*a)+(-c*a1)*b) by XCMPLX_1:175 .= a1*(c*b) + ((((-c)*a2)*a + (c*a2)*a)+(-c*a1)*b) by XCMPLX_1:4 .= a1*(c*b) + ((((-c*a2))*a + (c*a2)*a)+(-c*a1)*b) by XCMPLX_1:175 .= a1*(c*b) + ((-((c*a2)*a) + (c*a2)*a)+(-c*a1)*b) by XCMPLX_1:175 .= a1*(c*b) + (0+(-c*a1)*b) by XCMPLX_0:def 6 .= a1*(c*b) + -(a1*c)*b by XCMPLX_1:175 .= a1*(c*b) + -a1*(c*b) by XCMPLX_1:4 .= 0 by XCMPLX_0:def 6; hence (a*w+b*y)-u,((c*b)*w+(-c*a)*y)-v are_Ort_wrt w,y by A1,A8,GEOMTRAP:34; end; Lm6: for w,y being VECTOR of V,a,b,c,d being Real holds (a*w+b*y)-(c*w+d*y) = (a-c)*w+(b-d)*y proof let w,y be VECTOR of V, a,b,c,d be Real; thus (a*w+b*y)-(c*w+d*y) = b*y+(a*w-(c*w+d*y)) by RLVECT_1:42 .= b*y+((a*w-c*w)-d*y) by RLVECT_1:41 .= b*y+((a-c)*w-d*y) by RLVECT_1:49 .= ((a-c)*w+b*y)-d*y by RLVECT_1:42 .= (a-c)*w+(b*y-d*y) by RLVECT_1:42 .= (a-c)*w+(b-d)*y by RLVECT_1:49; end; Lm7: Gen w,y implies for a,b,c,d being Real st a*w + c*y = b*w + d*y holds a = b & c = d proof assume A1: Gen w,y; let a,b,c,d be Real; assume a*w+c*y=b*w+d*y; then 0.V = (a*w+c*y)-(b*w+d*y) by RLVECT_1:28 .= (a-b)*w+(c-d)*y by Lm6; then a-b=0 & c-d=0 by A1,ANALMETR:def 1; then -b + a =0 & -d + c = 0 by XCMPLX_0:def 8; then a=-(-b) & c = -(-d) by XCMPLX_0:def 6; hence thesis; end; canceled; theorem Th21: Gen w,y & MS = AMSpace(V,w,y) implies LIN_holds_in MS proof assume that A1: Gen w,y and A2: MS=AMSpace(V,w,y); now let o,a,a1,b,b1,c,c1 be Element of MS such that A3: o<>a & o<>a1 & o<>b & o<>b1 & o<>c & o<>c1 & a<>b and A4: o,c _|_ o,c1 & o,a _|_ o,a1 & o,b _|_ o,b1 and A5: not LIN o,c,a & LIN o,a,b & LIN o,a1,b1 and A6: a,c _|_ a1,c1 & b,c _|_ b1,c1; A7: not LIN o,c,b proof assume A8: LIN o,c,b; reconsider o'=o,a'=a,b'=b,c'=c as Element of Af(MS) by ANALMETR:47; LIN o',c',b' & LIN o',a',b' by A5,A8,ANALMETR:55; then LIN o',b',c' & LIN o',b',a' & LIN o',b',o' by AFF_1:15,16; then LIN o',c',a' by A3,AFF_1:17; hence contradiction by A5,ANALMETR:55; end ; reconsider q=o,u1=a,u2=b,u3=c,v1=a1,v2=b1,v3=c1 as VECTOR of V by A2,ANALMETR:28; q,u3,q,v3 are_Ort_wrt w,y & q,u1,q,v1 are_Ort_wrt w,y & q,u2,q,v2 are_Ort_wrt w,y by A2,A4,ANALMETR:31; then A9: u1-q,v1-q are_Ort_wrt w,y & u2-q,v2-q are_Ort_wrt w,y & u3-q,v3-q are_Ort_wrt w,y by ANALMETR:def 3; A10: u1-q<>0.V & u2-q<>0.V & u3-q<>0.V & v3-q<>0.V by A3,RLVECT_1:35; then consider r being Real such that A11: for a',b' being Real holds a'*w+b'*y,(r*b')*w+(-r*a')*y are_Ort_wrt w,y & (a'*w+b'*y)-(u3-q),((r*b')*w+(-r*a')*y)-(v3-q) are_Ort_wrt w,y by A1,A9,Th19; consider A1,A2 being Real such that A12:u1-q=A1*w+A2*y by A1,ANALMETR:def 1; consider B1,B2 being Real such that A13:u2-q=B1*w+B2*y by A1,ANALMETR:def 1; set v1'=((r*A2)*w+(-r*A1)*y)+q,v2'=((r*B2)*w+(-r*B1)*y)+q; reconsider a1'=v1',b1'=v2' as Element of MS by A2,ANALMETR:28; A14: v1'-q=(r*A2)*w+(-r*A1)*y & v2'-q=(r*B2)*w+(-r*B1)*y by RLSUB_2:78; then u1-q,v1'-q are_Ort_wrt w,y & u2-q,v2'-q are_Ort_wrt w,y by A11,A12,A13 ; then q,u1,q,v1' are_Ort_wrt w,y & q,u2,q,v2' are_Ort_wrt w,y by ANALMETR:def 3 ; then A15: o,a _|_ o,a1' & o,b _|_ o,b1' by A2,ANALMETR:31; (u1-q)-(u3-q)=u1-u3 & (u2-q)-(u3-q)=u2-u3 & (v1'-q)-(v3-q)=v1'-v3 & (v2'-q)-(v3-q)=v2'-v3 by Lm4; then u1-u3,v1'-v3 are_Ort_wrt w,y & u2-u3,v2'-v3 are_Ort_wrt w,y by A11,A12,A13 ,A14 ; then u3,u1,v3,v1' are_Ort_wrt w,y & u3,u2,v3,v2' are_Ort_wrt w,y by ANALMETR: def 3; then A16: c,a _|_ c1,a1' & c,b _|_ c1,b1' by A2,ANALMETR:31; c,a _|_ c1,a1 & c,b _|_ c1,b1 by A6,ANALMETR:83; then A17: a1=a1' & b1=b1' by A3,A4,A5,A7,A15,A16,Th16; o,a // o,b by A5,ANALMETR:def 11; then q,u1 '||' q,u2 by A2,GEOMTRAP:4; then q,u1 // q,u2 or q,u1 // u2,q by GEOMTRAP:def 1; then consider a',b' being Real such that A18: a'*(u1-q)=b'*(u2-q) and A19: a'<>0 or b'<>0 by ANALMETR:18; A20: now assume A21: b'=0; then 0.V = a'*(u1-q) by A18,RLVECT_1:23; hence contradiction by A10,A19,A21,RLVECT_1:24; end; set s=b'"*a'; A22: u2-q = b'"*(a'*(u1-q)) by A18,A20,ANALOAF:12 .= s*(u1-q) by RLVECT_1:def 9; then B1*w+B2*y = s*(A1*w)+s*(A2*y) by A12,A13,RLVECT_1:def 9 .= (s*A1)*w + s*(A2*y) by RLVECT_1:def 9 .= (s*A1)*w+(s*A2)*y by RLVECT_1:def 9; then A23: B1=s*A1 & B2=s*A2 by A1,Lm7; A24: v2'-q = (r*B2)*w+(-r*B1)*y by RLSUB_2:78 .= (r*B2)*w+(r*B1)*(-y) by RLVECT_1:38 .= (r*(s*A2))*w + -((r*(s*A1))*y) by A23,RLVECT_1:39 .= (r*(s*A2))*w - (r*(s*A1))*y by RLVECT_1:def 11 .= r*((s*A2)*w) - (r*(s*A1))*y by RLVECT_1:def 9 .= r*((s*A2)*w) - r*((s*A1)*y) by RLVECT_1:def 9 .= r*((s*A2)*w - (s*A1)*y) by RLVECT_1:48 .= r*(s*(A2*w) - (s*A1)*y) by RLVECT_1:def 9 .= r*(s*(A2*w) - s*(A1*y)) by RLVECT_1:def 9 .= r*(s*(A2*w - A1*y)) by RLVECT_1:48 .= (s*r)*(A2*w - A1*y) by RLVECT_1:def 9 .= s*(r*(A2*w - A1*y)) by RLVECT_1:def 9 .= s*(r*(A2*w) - r*(A1*y)) by RLVECT_1:48 .= s*((r*A2)*w - r*(A1*y)) by RLVECT_1:def 9 .= s*((r*A2)*w - (r*A1)*y) by RLVECT_1:def 9 .= s*((r*A2)*w + - (r*A1)*y) by RLVECT_1:def 11 .= s*((r*A2)*w + (r*A1)*(-y)) by RLVECT_1:39 .= s*((r*A2)*w + (-r*A1)*y) by RLVECT_1:38 .= s*(v1'-q) by RLSUB_2:78; 1*(u2-v2') = u2-v2' by RLVECT_1:def 9 .= s*(u1-q)-s*(v1'-q) by A22,A24,Lm4 .= s*((u1-q)-(v1'-q)) by RLVECT_1:48 .= s*(u1-v1') by Lm4; then v1',u1 // v2',u2 or v1',u1 // u2,v2' by ANALMETR:18; then v1',u1 '||' v2',u2 by GEOMTRAP:def 1; then a1',a // b1',b by A2,GEOMTRAP: 4; hence a,a1 // b,b1 by A17,ANALMETR:81; end; hence thesis by CONAFFM:def 5; end; theorem Th22: for o,a,a1,b,b1,c,c1 being Element of MS st o,a _|_ o,a1 & o,b _|_ o,b1 & o,c _|_ o,c1 & a,b _|_ a1,b1 & a,c _|_ a1,c1 & not o,c // o,a & not o,a // o,b & o=a1 holds b,c _|_ b1,c1 proof let o,a,a1,b,b1,c,c1 be Element of MS such that A1: o,a _|_ o,a1 & o,b _|_ o,b1 & o,c _|_ o,c1 and A2: a,b _|_ a1,b1 & a,c _|_ a1,c1 and A3: not o,c // o,a & not o,a // o,b and A4: o=a1; A5: o=b1 proof assume o<>b1; then a,b // o,b by A1,A2,A4,ANALMETR:85 ; then b,a // b,o by ANALMETR:81; then LIN b,a,o by ANALMETR:def 11; then LIN o,a,b by Th4; hence contradiction by A3,ANALMETR:def 11; end; o=c1 proof assume o<>c1; then a,c // o,c by A1,A2,A4,ANALMETR:85 ; then c,a // c,o by ANALMETR:81; then LIN c,a,o by ANALMETR:def 11; then LIN o,c,a by Th4; hence contradiction by A3,ANALMETR:def 11; end; hence thesis by A5,ANALMETR:80; end; theorem Th23: Gen w,y & MS = AMSpace(V,w,y) implies MS is Homogeneous proof assume that A1: Gen w,y and A2: MS=AMSpace(V,w,y); now let o,a,a1,b,b1,c,c1 be Element of MS such that A3: o,a _|_ o,a1 & o,b _|_ o,b1 & o,c _|_ o,c1 and A4: a,b _|_ a1,b1 & a,c _|_ a1,c1 and A5: not o,c // o,a & not o,a // o,b; reconsider q=o,u1=a,u2=b,u3=c,v1=a1,v2=b1,v3=c1 as VECTOR of V by A2,ANALMETR:28; A6: not LIN o,a,b & not LIN o,a,c proof assume not thesis; then o,a // o,b or o,a // o,c by ANALMETR:def 11; hence contradiction by A5,ANALMETR:81; end; then A7: o<>a & o<>b & o<>c by Th1; now assume A8: o<>a1; q,u3,q,v3 are_Ort_wrt w,y & q,u1,q,v1 are_Ort_wrt w,y & q,u2,q,v2 are_Ort_wrt w,y by A2,A3,ANALMETR:31; then A9: u1-q,v1-q are_Ort_wrt w,y & u2-q,v2-q are_Ort_wrt w,y & u3-q,v3-q are_Ort_wrt w,y by ANALMETR:def 3; u1-q<>0.V & v1-q<>0.V by A7,A8,RLVECT_1:35; then consider r being Real such that A10: for a',b' being Real holds a'*w+b'*y,(r*b')*w+(-r*a')*y are_Ort_wrt w,y & (a'*w+b'*y)-(u1-q),((r*b')*w+(-r*a')*y)-(v1-q) are_Ort_wrt w,y by A1,A9,Th19; consider A1,A2 being Real such that A11:u3-q=A1*w+A2*y by A1,ANALMETR:def 1; consider B1,B2 being Real such that A12:u2-q=B1*w+B2*y by A1,ANALMETR:def 1; set v3'=((r*A2)*w+(-r*A1)*y)+q,v2'=((r*B2)*w+(-r*B1)*y)+q; reconsider c1'=v3',b1'=v2' as Element of MS by A2,ANALMETR:28; A13: v3'-q=(r*A2)*w+(-r*A1)*y & v2'-q=(r*B2)*w+(-r*B1)*y by RLSUB_2:78; then u3-q,v3'-q are_Ort_wrt w,y & u2-q,v2'-q are_Ort_wrt w,y by A10,A11,A12 ; then q,u3,q,v3' are_Ort_wrt w,y & q,u2,q,v2' are_Ort_wrt w,y by ANALMETR:def 3 ; then A14: o,c _|_ o,c1' & o,b _|_ o,b1' by A2,ANALMETR:31; (u3-q)-(u1-q)=u3-u1 & (u2-q)-(u1-q)=u2-u1 & (v3'-q)-(v1-q)=v3'-v1 & (v2'-q)-(v1-q)=v2'-v1 by Lm4; then u3-u1,v3'-v1 are_Ort_wrt w,y & u2-u1,v2'-v1 are_Ort_wrt w,y by A10,A11,A12 ,A13 ; then u1,u3,v1,v3' are_Ort_wrt w,y & u1,u2,v1,v2' are_Ort_wrt w,y by ANALMETR: def 3; then a,c _|_ a1,c1' & a,b _|_ a1,b1' by A2,ANALMETR:31; then A15: c1=c1' & b1=b1' by A3,A4,A6,A8,A14,Th16; u3-u2 = (A1*w+A2*y)-(B1*w+B2*y) by A11,A12,Lm4 .= (A1-B1)*w+(A2-B2)*y by Lm6; then A16: pr1(w,y,u3-u2)=A1-B1 & pr2(w,y,u3-u2)=A2-B2 by A1,GEOMTRAP:def 4,def 5; v3'-v2' = ((r*A2)*w+(-r*A1)*y) - ((r*B2)*w+(-r*B1)*y) by Lm4 .= ((r*A2)*w+(r*(-A1))*y) - ((r*B2)*w+(-r*B1)*y) by XCMPLX_1:175 .= ((r*A2)*w+(r*(-A1))*y) - ((r*B2)*w+(r*(-B1))*y) by XCMPLX_1:175 .= (r*A2-r*B2)*w + (r*(-A1)-r*(-B1))*y by Lm6 .= (r*A2-r*B2)*w + (r*((-A1)-(-B1)))*y by XCMPLX_1:40 .= (r*(A2-B2))*w + (r*((-A1)-(-B1)))*y by XCMPLX_1:40 .= (r*(A2-B2))*w + (r*(-(-B1) + (-A1)))*y by XCMPLX_0:def 8 .= (r*(A2-B2))*w + (r*(B1 -A1))*y by XCMPLX_0:def 8; then pr1(w,y,v3'-v2')=r*(A2-B2) & pr2(w,y,v3'-v2')=r*(B1-A1) by A1,GEOMTRAP:def 4,def 5; then PProJ (w,y,u3-u2,v3'-v2') = (A1-B1)*(r*(A2-B2)) + (A2-B2)*(r*(B1-A1)) by A16,GEOMTRAP :def 6 .=(A2-B2)*((A1-B1)*r) + (A2-B2)*(r*(B1-A1)) by XCMPLX_1:4 .= (A2-B2)*(r*(A1-B1) + r*(B1-A1)) by XCMPLX_1:8 .= (A2-B2)*(r*((A1-B1) + (B1-A1))) by XCMPLX_1:8 .= ((A2-B2)*r)*((A1-B1) + (B1-A1)) by XCMPLX_1:4 .= ((A2-B2)*r)*((A1-B1) + (B1+-A1)) by XCMPLX_0:def 8 .= ((A2-B2)*r)*((A1+-B1) + (B1+-A1)) by XCMPLX_0:def 8 .= ((A2-B2)*r)*(A1+(-B1 + (B1+-A1))) by XCMPLX_1:1 .= ((A2-B2)*r)*(A1+((-B1 + B1)+-A1)) by XCMPLX_1:1 .= ((A2-B2)*r)*(A1+(0+-A1)) by XCMPLX_0:def 6 .= ((A2-B2)*r)*0 by XCMPLX_0:def 6 .=0; then u3-u2,v3'-v2' are_Ort_wrt w,y by A1,GEOMTRAP:34; then u2,u3,v2',v3' are_Ort_wrt w,y by ANALMETR:def 3;hence b,c _|_ b1,c1 by A2 ,A15,ANALMETR:31; end; hence b,c _|_ b1,c1 by A3,A4,A5,Th22; end; hence thesis by Def7; end; definition cluster Euclidean Pappian Desarguesian Homogeneous translation Fanoian Moufangian OrtAfPl; existence proof consider V such that A1: ex w,y st Gen w,y by ANALMETR:7; consider w,y such that A2: Gen w,y by A1; reconsider MS=AMSpace(V,w,y) as OrtAfPl by A2,ANALMETR:46; take MS; LIN_holds_in MS by A2,Th21; then A3: 3H_holds_in MS by CONAFFM:6; (for a,b being Real st a*w + b*y = 0.V holds a=0 & b=0) & (for u being VECTOR of V ex a,b being Real st u = a*w + b*y) by A2,ANALMETR:def 1; then reconsider OAS=OASpace(V) as OAffinSpace by ANALOAF:38; A4: Af(MS)=Lambda(OAS) by ANALMETR:30; then A5: Af(MS) is Pappian by PAPDESAF:19; A6: Af(MS) is Desarguesian by A4,PAPDESAF:20; A7: Af(MS) is Moufangian by A4,PAPDESAF:22; Af(MS) is translational by A4,PAPDESAF:23; hence thesis by A2,A3,A4,A5,A6,A7,Def2,Def3,Def4,Def5,Def6,Th8,Th23; end; end; definition cluster Euclidean Pappian Desarguesian Homogeneous translation Fanoian Moufangian OrtAfSp; existence proof consider MS being Euclidean Pappian Desarguesian Homogeneous translation Fanoian Moufangian OrtAfPl; MS is Euclidean Pappian Desarguesian Homogeneous translation Fanoian Moufangian; hence thesis; end; end; theorem Gen w,y & MS=AMSpace(V,w,y) implies MS is Euclidean Pappian Desarguesian Homogeneous translation Fanoian Moufangian OrtAfPl proof assume A1: Gen w,y & MS=AMSpace(V,w,y); then reconsider MS'=AMSpace(V,w,y) as OrtAfPl; LIN_holds_in MS' by A1,Th21 ; then A2: 3H_holds_in MS' by CONAFFM:6; (for a,b being Real st a*w + b*y = 0.V holds a=0 & b=0) & (for u being VECTOR of V ex a,b being Real st u = a*w + b*y) by A1,ANALMETR:def 1; then reconsider OAS=OASpace(V) as OAffinSpace by ANALOAF:38; A3: Af(MS')=Lambda(OAS) by ANALMETR:30; then A4: Af(MS') is Pappian by PAPDESAF:19; A5: Af(MS') is Desarguesian by A3,PAPDESAF:20; A6: Af(MS') is Moufangian by A3,PAPDESAF:22; Af(MS') is translational by A3,PAPDESAF:23; hence thesis by A1,A2,A3,A4,A5,A6,Def2,Def3,Def4,Def5,Def6,Th8,Th23; end; definition let MS be Pappian OrtAfPl; cluster Af(MS) -> Pappian; correctness by Def2; end; definition let MS be Desarguesian OrtAfPl; cluster Af(MS) -> Desarguesian; correctness by Def3; end; definition let MS be Moufangian OrtAfPl; cluster Af(MS) -> Moufangian; correctness by Def5; end; definition let MS be translation OrtAfPl; cluster Af(MS) -> translational; correctness by Def6; end; definition let MS be Fanoian OrtAfPl; cluster Af(MS) -> Fanoian; correctness by Def4; end; definition let MS be Homogeneous OrtAfPl; cluster Af(MS) -> Desarguesian; correctness proof MS is Desarguesian by Th14;hence thesis by Def3; end; end; definition let MS be Euclidean Desarguesian OrtAfPl; cluster Af(MS) -> Pappian; correctness proof MS is Pappian by Th15;hence thesis by Def2; end; end; definition let MS be Pappian OrtAfSp; cluster Af(MS) -> Pappian; correctness by Def2; end; definition let MS be Desarguesian OrtAfSp; cluster Af(MS) -> Desarguesian; correctness by Def3; end; definition let MS be Moufangian OrtAfSp; cluster Af(MS) -> Moufangian; correctness by Def5; end; definition let MS be translation OrtAfSp; cluster Af(MS) -> translational; correctness by Def6; end; definition let MS be Fanoian OrtAfSp; cluster Af(MS) -> Fanoian; correctness by Def4; end;