The Mizar article:

Oriented Metric-Affine Plane --- Part II

by
Jaroslaw Zajkowski

Received June 19, 1992

Copyright (c) 1992 Association of Mizar Users

MML identifier: DIRORT
[ MML identifier index ]


environ

 vocabulary RLVECT_1, ANALOAF, ANALMETR, ANALORT, SYMSP_1, DIRORT;
 notation STRUCT_0, RLVECT_1, ANALOAF, ANALMETR, ANALORT;
 constructors ANALMETR, ANALORT, XBOOLE_0;
 clusters ANALOAF, ANALORT, ZFMISC_1, XBOOLE_0;
 theorems ANALMETR, ANALORT;

begin

 reserve V for RealLinearSpace;

 reserve x,y for VECTOR of V;

definition let AS be non empty AffinStruct;
           let a,b,c,d be Element of AS;
  redefine pred a,b // c,d;
  synonym a,b '//' c,d;
end;

theorem
Th1:Gen x,y implies (for u,u1,v,v1,w,w1,w2 being
  Element of CESpace(V,x,y) holds
  ((u,u '//' v,w) & (u,v '//' w,w) &
  (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
  (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
  (u,v '//' u1,v1 implies v,u '//' v1,u1) &
  (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
  (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u))) &
  (for u,v,w being Element of CESpace(V,x,y) holds
  ex u1 being Element of CESpace(V,x,y) st
  w<>u1 & w,u1 '//' u,v ) &
  (for u,v,w being Element of CESpace(V,x,y) holds
  ex u1 being Element of CESpace(V,x,y) st
  w<>u1 & u,v '//' w,u1 )
proof
  assume A1:Gen x,y;
  set S=CESpace(V,x,y);
A2:  S=AffinStruct (# the carrier of V,CORTE(V,x,y) #) by ANALORT:def 7;
  thus (for u,u1,v,v1,w,w1,w2 being Element of S holds
  ((u,u '//' v,w) & (u,v '//' w,w) &
  (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
  (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
  (u,v '//' u1,v1 implies v,u '//' v1,u1) &
  (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
  (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u)))
  proof
    let u,u1,v,v1,w,w1,w2 be Element of S;
    reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1 as
    Element of V by A2;
    thus u,u '//' v,w
    proof
      u',u',v',w' are_COrte_wrt x,y by ANALORT:20;
    hence thesis by ANALORT:56;
    end;
 thus u,v '//' w,w
 proof
     u',v',w',w' are_COrte_wrt x,y by ANALORT:22;
   hence thesis by ANALORT:56;
 end;
 thus (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1)
 proof
     (u',v',u1',v1' are_COrte_wrt x,y & u',v',v1',u1' are_COrte_wrt x,y
   implies u'=v' or u1'=v1') by A1,ANALORT:30;
   hence thesis by ANALORT:56;
 end;
 thus (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1)
 proof
     (u',v',u1',v1' are_COrte_wrt x,y & u',v',u1',w' are_COrte_wrt x,y
   implies u',v',v1',w' are_COrte_wrt x,y or u',v',w',v1' are_COrte_wrt x,y)
   by A1,ANALORT:32;
   hence thesis by ANALORT:56;
 end;
 thus (u,v '//' u1,v1 implies v,u '//' v1,u1)
 proof
     (u',v',u1',v1' are_COrte_wrt x,y implies v',u',v1',u1' are_COrte_wrt x,y)
   by ANALORT:34;
   hence thesis by ANALORT:56;
 end;
 thus (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w)
 proof
     (u',v',u1',v1' are_COrte_wrt x,y & u',v',v1',w' are_COrte_wrt x,y
   implies u',v',u1',w' are_COrte_wrt x,y) by A1,ANALORT:36;
   hence thesis by ANALORT:56;
 end;
 thus (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u)
 proof
     (u',u1',v',v1' are_COrte_wrt x,y implies v',v1',u',u1' are_COrte_wrt x,y
   or v',v1',u1',u' are_COrte_wrt x,y) by A1,ANALORT:18;
   hence thesis by ANALORT:56;
 end;
 thus thesis;
 end;
 thus (for u,v,w being Element of S holds
      ex u1 being Element of S st
      w<>u1 & w,u1 '//' u,v )
 proof
   let u,v,w be Element of S;
   reconsider u'=u,v'=v,w'=w as Element of V by A2;
   consider u1' being Element of V such that
   A3: w'<>u1' & w',u1',u',v' are_COrte_wrt x,y by A1,ANALORT:38;
   reconsider u1=u1' as Element of S by A2;
     w<>u1 & w,u1 '//' u,v by A3,ANALORT:56;
   hence thesis;
 end;
   let u,v,w be Element of S;
   reconsider u'=u,v'=v,w'=w as Element of V by A2;
   consider u1' being Element of V such that
   A4: w'<>u1' & u',v',w',u1' are_COrte_wrt x,y by A1,ANALORT:40;
   reconsider u1=u1' as Element of S by A2;
     w<>u1 & u,v '//' w,u1 by A4,ANALORT:56;
   hence thesis;
end;

theorem
Th2:    Gen x,y implies
(for u,u1,v,v1,w,w1,w2 being Element of CMSpace(V,x,y) holds
((u,u '//' v,w) & (u,v '//' w,w) &
 (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
 (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
 (u,v '//' u1,v1 implies v,u '//' v1,u1) &
 (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
 (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u))) &
(for u,v,w being Element of CMSpace(V,x,y) holds
  ex u1 being Element of CMSpace(V,x,y) st
   w<>u1 & w,u1 '//' u,v ) &
(for u,v,w being Element of CMSpace(V,x,y) holds
  ex u1 being Element of CMSpace(V,x,y) st
   w<>u1 & u,v '//' w,u1 )
proof
  assume A1:Gen x,y;
  set S=CMSpace(V,x,y);
A2:  S=AffinStruct (# the carrier of V,CORTM(V,x,y) #) by ANALORT:def 8;
  thus
    (for u,u1,v,v1,w,w1,w2 being Element of S holds
  ((u,u '//' v,w) & (u,v '//' w,w) &
  (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
  (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
  (u,v '//' u1,v1 implies v,u '//' v1,u1) &
  (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
  (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u)))
  proof
    let u,u1,v,v1,w,w1,w2 be Element of S;
    reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1 as
    Element of V by A2;
    thus u,u '//' v,w proof u',u',v',w' are_COrtm_wrt x,y by ANALORT:21;
    hence thesis by ANALORT:57;
  end;
  thus u,v '//' w,w
  proof
      u',v',w',w' are_COrtm_wrt x,y by ANALORT:23;
    hence thesis by ANALORT:57;
  end;
  thus (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1)
  proof
      (u',v',u1',v1' are_COrtm_wrt x,y & u',v',v1',u1' are_COrtm_wrt x,y
    implies u'=v' or u1'=v1') by A1,ANALORT:31;
    hence thesis by ANALORT:57;
  end;
  thus (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1)
  proof
      (u',v',u1',v1' are_COrtm_wrt x,y & u',v',u1',w' are_COrtm_wrt x,y
    implies u',v',v1',w' are_COrtm_wrt x,y or u',v',w',v1' are_COrtm_wrt x,y)
    by A1,ANALORT:33;
    hence thesis by ANALORT:57;
  end;
  thus (u,v '//' u1,v1 implies v,u '//' v1,u1)
  proof
      (u',v',u1',v1' are_COrtm_wrt x,y implies v',u',v1',u1' are_COrtm_wrt x,y)
    by ANALORT:35;
    hence thesis by ANALORT:57;
  end;
  thus (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w)
  proof
      (u',v',u1',v1' are_COrtm_wrt x,y & u',v',v1',w' are_COrtm_wrt x,y
    implies u',v',u1',w' are_COrtm_wrt x,y) by A1,ANALORT:37;
    hence thesis by ANALORT:57;
  end;
  thus (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u)
  proof
      (u',u1',v',v1' are_COrtm_wrt x,y implies v',v1',u',u1' are_COrtm_wrt x,y
    or v',v1',u1',u' are_COrtm_wrt x,y) by A1,ANALORT:19;
    hence thesis by ANALORT:57;
  end;
  thus thesis;
 end;
  thus (for u,v,w being Element of S holds
       ex u1 being Element of S st
      w<>u1 & w,u1 '//' u,v )
  proof
    let u,v,w be Element of S;
    reconsider u'=u,v'=v,w'=w as Element of V by A2;
    consider u1' being Element of V such that
    A3: w'<>u1' & w',u1',u',v' are_COrtm_wrt x,y by A1,ANALORT:39;
    reconsider u1=u1' as Element of S by A2;
      w<>u1 & w,u1 '//' u,v by A3,ANALORT:57;
    hence thesis;
  end;
    let u,v,w be Element of S;
    reconsider u'=u,v'=v,w'=w as Element of V by A2;
    consider u1' being Element of V such that
    A4: w'<>u1' & u',v',w',u1' are_COrtm_wrt x,y by A1,ANALORT:41;
    reconsider u1=u1' as Element of S by A2;
      w<>u1 & u,v '//' w,u1 by A4,ANALORT:57;
    hence thesis;
end;

definition let IT be non empty AffinStruct;
  attr IT is Oriented_Orthogonality_Space-like means
  :Def1: (for u,u1,v,v1,w,w1,w2 being Element of IT holds
  ((u,u '//' v,w) & (u,v '//' w,w) &
  (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
  (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
  (u,v '//' u1,v1 implies v,u '//' v1,u1) &
  (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
  (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u))) &
  (for u,v,w being Element of IT holds
  ex u1 being Element of IT st
  w<>u1 & w,u1 '//' u,v ) &
  (for u,v,w being Element of IT holds
  ex u1 being Element of IT st
  w<>u1 & u,v '//' w,u1 );
end;

definition
  cluster Oriented_Orthogonality_Space-like (non empty AffinStruct);
  existence
   proof
     consider V,x,y such that A1:Gen x,y by ANALMETR:7;
     take C = CESpace(V,x,y);
     thus (for u,u1,v,v1,w,w1,w2 being Element of C holds
  ((u,u '//' v,w) & (u,v '//' w,w) &
  (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
  (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
  (u,v '//' u1,v1 implies v,u '//' v1,u1) &
  (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
  (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u))) &
  (for u,v,w being Element of C holds
  ex u1 being Element of C st
  w<>u1 & w,u1 '//' u,v ) &
  (for u,v,w being Element of C holds
  ex u1 being Element of C st
  w<>u1 & u,v '//' w,u1 ) by A1,Th1;
   end;
 end;

definition
  mode Oriented_Orthogonality_Space is Oriented_Orthogonality_Space-like
   (non empty AffinStruct);
end;

canceled;

theorem
Th4:Gen x,y implies CMSpace(V,x,y) is Oriented_Orthogonality_Space
proof
assume Gen x,y;
then (for u,u1,v,v1,w,w1,w2 being Element of CMSpace(V,x,y)
holds
((u,u '//' v,w) & (u,v '//' w,w) &
 (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
 (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
 (u,v '//' u1,v1 implies v,u '//' v1,u1) &
 (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
 (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u))) &
(for u,v,w being Element of CMSpace(V,x,y) holds
  ex u1 being Element of CMSpace(V,x,y) st
   w<>u1 & w,u1 '//' u,v ) &
(for u,v,w being Element of CMSpace(V,x,y) holds
  ex u1 being Element of CMSpace(V,x,y) st
   w<>u1 & u,v '//' w,u1 ) by Th2;
  hence thesis by Def1;
end;

theorem
Th5:Gen x,y implies CESpace(V,x,y) is Oriented_Orthogonality_Space
proof
assume Gen x,y;
then (for u,u1,v,v1,w,w1,w2 being Element of CESpace(V,x,y)
holds
((u,u '//' v,w) & (u,v '//' w,w) &
 (u,v '//' u1,v1 & u,v '//' v1,u1 implies u=v or u1=v1) &
 (u,v '//' u1,v1 & u,v '//' u1,w implies u,v '//' v1,w or u,v '//' w,v1) &
 (u,v '//' u1,v1 implies v,u '//' v1,u1) &
 (u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w) &
 (u,u1 '//' v,v1 implies v,v1 '//' u,u1 or v,v1 '//' u1,u))) &
(for u,v,w being Element of CESpace(V,x,y) holds
  ex u1 being Element of CESpace(V,x,y) st
   w<>u1 & w,u1 '//' u,v ) &
(for u,v,w being Element of CESpace(V,x,y) holds
  ex u1 being Element of CESpace(V,x,y) st
   w<>u1 & u,v '//' w,u1 ) by Th1;
  hence thesis by Def1;
end;

reserve AS for Oriented_Orthogonality_Space;
reserve u,u1,u2,u3,v,v1,v2,v3,w,w1 for Element of AS;


theorem
  for u,v,w being Element of AS holds
  ex u1 being Element of AS st
    u1,w '//' u,v & u1<>w
proof
let u,v,w;
consider u1 such that A1:u1<>w & w,u1 '//' v,u by Def1;
  u1,w '//' u,v by A1,Def1;
hence thesis by A1;
end;

canceled;

theorem
  for u,v,w being Element of AS holds
  ex u1 being Element of AS st
   u<>u1 & (v,w '//' u,u1 or v,w '//' u1,u)
proof
let u,v,w;
consider u1 such that A1:u<>u1 & u,u1 '//' v,w by Def1;
     u<>u1 & (v,w '//' u,u1 or v,w '//' u1,u) by A1,Def1;
   hence thesis;
   end;

definition
  let AS be Oriented_Orthogonality_Space;
  let a,b,c,d be Element of AS;
  pred a,b _|_ c,d means a,b '//' c,d or a,b '//' d,c;
end;

definition
  let AS be Oriented_Orthogonality_Space;
  let a,b,c,d be Element of AS;
  pred a,b // c,d means
  :Def3:ex e,f being Element of AS
  st ( e<>f & e,f '//' a,b & e,f '//' c,d);
end;

definition let IT be Oriented_Orthogonality_Space;
  attr IT is bach_transitive means
  :Def4: for u,u1,u2,v,v1,v2,w,w1 being Element of IT holds
     ( (u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2 )
        implies (w=w1 or v=v1 or u,u1 '//' u2,v2) );
end;

definition let IT be Oriented_Orthogonality_Space;
  attr IT is right_transitive means
  :Def5: for u,u1,u2,v,v1,v2,w,w1 being Element of IT holds
   ( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
       implies (w=w1 or v=v1 or u,u1 '//' u2,v2) );
end;

definition let IT be Oriented_Orthogonality_Space;
  attr IT is left_transitive means
  :Def6: for u,u1,u2,v,v1,v2,w,w1 being Element of IT holds
   ( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1) );
end;

definition let IT be Oriented_Orthogonality_Space;
  attr IT is Euclidean_like means
  :Def7:for u,u1,v,v1 being Element of IT holds
  (u,u1 '//' v,v1 implies v,v1 '//' u1,u );
end;

definition let IT be Oriented_Orthogonality_Space;
  attr IT is Minkowskian_like means
  :Def8:for u,u1,v,v1 being Element of IT
      holds (u,u1 '//' v,v1 implies v,v1 '//' u,u1 );
end;

theorem
  u,u1 // w,w & w,w // u,u1
proof consider v; consider v1 such that A1: v1<>v & v,v1 '//' u,u1 by Def1;
  v,v1 '//' w,w by Def1;
hence thesis by A1,Def3;
end;

theorem
  u,u1 // v,v1 implies v,v1 // u,u1
proof
assume u,u1 // v,v1;
then ex w,w1 st w<>w1 &
w,w1 '//' u,u1 & w,w1 '//' v,v1 by Def3;
hence thesis by Def3;
end;

theorem
  u,u1 // v,v1 implies u1,u // v1,v
proof assume u,u1 // v,v1;
then consider w,w1 such that
A1:w<>w1 & w,w1 '//' u,u1 & w,w1 '//' v,v1 by Def3;
  w1<>w & w1,w '//' u1,u & w1,w '//' v1,v by A1,Def1;
hence thesis by Def3;end;

theorem
  AS is left_transitive iff (for v,v1,w,w1,u2,v2 holds
 (v,v1 // u2,v2 & v,v1 '//' w,w1 & v<>v1 implies u2,v2 '//' w,w1))
proof
A1:AS is left_transitive implies (for v,v1,w,w1,u2,v2 holds
 (v,v1 // u2,v2 & v,v1 '//' w,w1 & v<>v1 implies u2,v2 '//' w,w1))
 proof
assume A2: AS is left_transitive;

let v,v1,w,w1,u2,v2;
assume A3:v,v1 // u2,v2 & v,v1 '//' w,w1 & v<>v1;
then ex u,u1 st u<>u1 &
u,u1 '//' v,v1 & u,u1 '//' u2,v2 by Def3;
hence thesis by A2,A3,Def6;
end;
   (for v,v1,w,w1,u2,v2 holds
 (v,v1 // u2,v2 & v,v1 '//' w,w1 & v<>v1 implies u2,v2 '//' w,w1))
implies AS is left_transitive
proof
   (for v,v1,w,w1,u2,v2 holds
 (v,v1 // u2,v2 & v,v1 '//' w,w1 & v<>v1 implies u2,v2 '//' w,w1))
implies (for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
   ( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1) ) )
  proof
assume A4: (for v,v1,w,w1,u2,v2 holds
 (v,v1 // u2,v2 & v,v1 '//' w,w1 & v<>v1 implies u2,v2 '//' w,w1));
 let u,u1,u2,v,v1,v2,w,w1;
  assume A5: (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 );
    now assume u<>u1 & v<>v1;
  then v,v1 // u2,v2 by A5,Def3;
  hence thesis by A4,A5;
  end;
 hence thesis;
end;
hence thesis by Def6;
end;
hence thesis by A1;
end;

theorem
Th13: AS is bach_transitive iff (for u,u1,u2,v,v1,v2 holds
  (u,u1 '//' v,v1 & v,v1 // u2,v2 & v<>v1 implies u,u1 '//' u2,v2))
proof
A1:AS is bach_transitive implies (for u,u1,u2,v,v1,v2 holds
  (u,u1 '//' v,v1 & v,v1 // u2,v2 & v<>v1 implies u,u1 '//' u2,v2))
proof
assume A2: AS is bach_transitive;
let u,u1,u2,v,v1,v2;
assume A3:u,u1 '//' v,v1 & v,v1 // u2,v2 & v<>v1;
 then ex w,w1 st w<>w1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2 by Def3;
hence thesis by A2,A3,Def4;
end;
   (for u,u1,u2,v,v1,v2 holds
  (u,u1 '//' v,v1 & v,v1 // u2,v2 & v<>v1 implies u,u1 '//' u2,v2))
implies AS is bach_transitive
proof
   (for u,u1,u2,v,v1,v2 holds
  (u,u1 '//' v,v1 & v,v1 // u2,v2 & v<>v1 implies u,u1 '//' u2,v2))
implies
   for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
     ( (u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2 )
        implies (w=w1 or v=v1 or u,u1 '//' u2,v2) )
proof
assume A4: (for u,u1,u2,v,v1,v2 holds
  (u,u1 '//' v,v1 & v,v1 // u2,v2 & v<>v1 implies u,u1 '//' u2,v2));
let u,u1,u2,v,v1,v2,w,w1;
assume A5:u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2;
  now assume w<>w1 & v<>v1;
 then v,v1 // u2,v2 by A5,Def3;
 hence thesis by A4,A5;
end;
hence thesis;
end;
hence thesis by Def4;
end;
hence thesis by A1;
end;

theorem
  AS is bach_transitive implies for u,u1,v,v1,w,w1 holds (u,u1 // v,v1 &
v,v1 // w,w1 & v<>v1 implies u,u1 // w,w1)
proof assume A1:AS is bach_transitive;
let u,u1,v,v1,w,w1;
assume that A2: u,u1 // v,v1 and A3: v,v1 // w,w1 and A4: v<>v1;
consider v2,v3 such that
A5: v2<>v3 and A6: v2,v3 '//' u,u1 and A7: v2,v3 '//' v,v1 by A2,Def3;
  v2,v3 '//' w,w1 by A1,A3,A4,A7,Th13;
hence thesis by A5,A6,Def3;
end;

theorem
Th15: Gen x,y & AS=CESpace(V,x,y) implies AS is
Euclidean_like left_transitive right_transitive bach_transitive
proof
assume A1:Gen x,y & AS=CESpace(V,x,y);
  A2: CESpace(V,x,y)=AffinStruct (# the carrier of V,CORTE(V,x,y) #)
  by ANALORT:def 7;

A3: now let
 u,u1,u2,v,v1,v2,w,w1 be Element of AS;
 thus
   ((u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 ))
  proof
reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1,w1'=w1,u2'=u2,v2'=v2 as
Element of V by A1,A2;
  (u',u1',v',v1' are_COrte_wrt x,y & w',w1',v',v1' are_COrte_wrt x,y &
w',w1',u2',v2' are_COrte_wrt x,y) implies (w'=w1' or v'=v1' or
u',u1',u2',v2' are_COrte_wrt x,y) by A1,ANALORT:42;
hence thesis by A1,ANALORT:56;
  end;
 end;
A4: now let u,u1,u2,v,v1,v2,w,w1 be Element of AS;
  thus ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 ))
  proof
reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1,w1'=w1,u2'=u2,v2'=v2 as
Element of V by A1,A2;
  (u',u1',v',v1' are_COrte_wrt x,y & v',v1',w',w1' are_COrte_wrt x,y &
u2',v2',w',w1' are_COrte_wrt x,y) implies (w'=w1' or v'=v1' or
u',u1',u2',v2' are_COrte_wrt x,y) by A1,ANALORT:46;
hence thesis by A1,ANALORT:56;
  end;
  end;
A5: now let u,u1,u2,v,v1,v2,w,w1 be Element of AS;
  thus ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 ))
  proof
reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1,w1'=w1,u2'=u2,v2'=v2 as
Element of V by A1,A2;
  (u',u1',v',v1' are_COrte_wrt x,y & v',v1',w',w1' are_COrte_wrt x,y &
u',u1',u2',v2' are_COrte_wrt x,y) implies (u'=u1' or v'=v1' or
u2',v2',w',w1' are_COrte_wrt x,y) by A1,ANALORT:48;
hence thesis by A1,ANALORT:56;
  end;
  end;
   now let u,u1,v,v1 be Element of AS;
  thus (u,u1 '//' v,v1 implies v,v1 '//' u1,u )
  proof
reconsider u'=u,v'=v,u1'=u1,v1'=v1 as
Element of V by A1,A2;
  u',u1',v',v1' are_COrte_wrt x,y implies
v',v1',u1',u' are_COrte_wrt x,y by A1,ANALORT:18;
hence thesis by A1,ANALORT:56;
  end;
  end;
hence thesis by A3,A4,A5,Def4,Def5,Def6,Def7;
end;

definition
  cluster Euclidean_like left_transitive right_transitive bach_transitive
          Oriented_Orthogonality_Space;
existence
proof consider V,x,y such that A1:Gen x,y by ANALMETR:7;
reconsider AS=CESpace(V,x,y) as Oriented_Orthogonality_Space by A1,Th5;
take AS; thus thesis by A1,Th15;
end; end;

theorem
Th16:Gen x,y & AS=CMSpace(V,x,y) implies AS is Minkowskian_like
left_transitive right_transitive bach_transitive
proof
assume A1:Gen x,y & AS=CMSpace(V,x,y);
  A2: CMSpace(V,x,y)=AffinStruct (# the carrier of V,CORTM(V,x,y) #)
  by ANALORT:def 8;

A3: now let
 u,u1,u2,v,v1,v2,w,w1 be Element of AS;
 thus
   ((u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 ))
  proof
reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1,w1'=w1,u2'=u2,v2'=v2 as
Element of V by A1,A2;
  (u',u1',v',v1' are_COrtm_wrt x,y & w',w1',v',v1' are_COrtm_wrt x,y &
w',w1',u2',v2' are_COrtm_wrt x,y) implies (w'=w1' or v'=v1' or
u',u1',u2',v2' are_COrtm_wrt x,y) by A1,ANALORT:43;
hence thesis by A1,ANALORT:57;
  end;
 end;
A4: now let u,u1,u2,v,v1,v2,w,w1 be Element of AS;
  thus ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 ))
  proof
reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1,w1'=w1,u2'=u2,v2'=v2 as
Element of V by A1,A2;
  (u',u1',v',v1' are_COrtm_wrt x,y & v',v1',w',w1' are_COrtm_wrt x,y &
u2',v2',w',w1' are_COrtm_wrt x,y) implies (w'=w1' or v'=v1' or
u',u1',u2',v2' are_COrtm_wrt x,y) by A1,ANALORT:47;
hence thesis by A1,ANALORT:57;
  end;
  end;
A5: now let u,u1,u2,v,v1,v2,w,w1 be Element of AS;
  thus ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 ))
  proof
reconsider u'=u,v'=v,w'=w,u1'=u1,v1'=v1,w1'=w1,u2'=u2,v2'=v2 as
Element of V by A1,A2;
  (u',u1',v',v1' are_COrtm_wrt x,y & v',v1',w',w1' are_COrtm_wrt x,y &
u',u1',u2',v2' are_COrtm_wrt x,y) implies (u'=u1' or v'=v1' or
u2',v2',w',w1' are_COrtm_wrt x,y) by A1,ANALORT:49;
hence thesis by A1,ANALORT:57;
  end;
  end;
   now let u,u1,v,v1 be Element of AS;
  thus (u,u1 '//' v,v1 implies v,v1 '//' u,u1 )
  proof
reconsider u'=u,v'=v,u1'=u1,v1'=v1 as Element of V by A1,A2;
  u',u1',v',v1' are_COrtm_wrt x,y implies
v',v1',u',u1' are_COrtm_wrt x,y by A1,ANALORT:19;
hence thesis by A1,ANALORT:57;
  end;
  end;
hence thesis by A3,A4,A5,Def4,Def5,Def6,Def8;
end;

definition
  cluster Minkowskian_like left_transitive right_transitive bach_transitive
          Oriented_Orthogonality_Space;
existence
proof consider V,x,y such that A1:Gen x,y by ANALMETR:7;
reconsider AS=CMSpace(V,x,y) as Oriented_Orthogonality_Space by A1,Th4;
take AS; thus thesis by A1,Th16;
end;
end;

theorem
Th17:AS is left_transitive implies AS is right_transitive
proof
  (for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 )))implies
(for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
  ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 )))
  proof
  assume A1:for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 ));
let u,u1,u2,v,v1,v2,w,w1;
  assume A2:
  (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 );

A3:( w=w1 or v=v1 or u,u1 '//' u2,v2 or u,u1 '//' v2,u2 ) implies
 (w=w1 or v=v1 or u,u1 '//' u2,v2 )
proof
    now
   A4: u=u1 implies thesis by Def1;
       now assume v2,u2 '//' w,w1;
         then u2,v2 '//' w1,w by Def1;
         then u2=v2 or w=w1 by A2,Def1;
         hence thesis;
         end;
     hence thesis by A1,A2,A4;
     end;
  hence thesis;
end;
 A5:now assume w,w1 '//' v,v1 & v,v1 '//' u,u1 & w,w1 '//' u2,v2;
 then w=w1 or v=v1 or u2,v2 '//' u,u1 by A1;
 hence thesis by A3,Def1;
 end;
 A6:now assume w,w1 '//' v,v1 & v,v1 '//' u,u1 & w,w1 '//' v2,u2;
 then w=w1 or v=v1 or v2,u2 '//' u,u1 by A1;
 hence thesis by A3,Def1;
 end;
 A7:now assume w,w1 '//' v,v1 & v,v1 '//' u1,u & w,w1 '//' u2,v2;
 then w=w1 or v=v1 or u2,v2 '//' u1,u by A1;
 then w=w1 or v=v1 or u1,u '//' u2,v2 or u1,u '//' v2,u2 by Def1;
 hence thesis by A3,Def1;
 end;
 A8:now assume w,w1 '//' v,v1 & v,v1 '//' u1,u & w,w1 '//' v2,u2;
 then w=w1 or v=v1 or v2,u2 '//' u1,u by A1;
 then w=w1 or v=v1 or u1,u '//' u2,v2 or u1,u '//' v2,u2 by Def1;
 hence thesis by A3,Def1;
 end;
 A9:now assume w,w1 '//' v1,v & v,v1 '//' u,u1 & w,w1 '//' u2,v2;
 then w,w1 '//' v1,v & v1,v '//' u1,u & w,w1 '//' u2,v2 by Def1;
 then w=w1 or v=v1 or u2,v2 '//' u1,u by A1;
 then w=w1 or v=v1 or v2,u2 '//' u,u1 by Def1;
 hence thesis by A3,Def1;
 end;
 A10:now assume w,w1 '//' v1,v & v,v1 '//' u,u1 & w,w1 '//' v2,u2;
 then w,w1 '//' v1,v & v1,v '//' u1,u & w,w1 '//' v2,u2 by Def1;
 then w=w1 or v=v1 or v2,u2 '//' u1,u by A1;
 then w=w1 or v=v1 or u2,v2 '//' u,u1 by Def1;
 hence thesis by A3,Def1;
 end;
 A11:now assume w,w1 '//' v1,v & v,v1 '//' u1,u & w,w1 '//' u2,v2;
 then w,w1 '//' v1,v & v1,v '//' u,u1 & w,w1 '//' u2,v2 by Def1;
 then w=w1 or v1=v or u2,v2 '//' u,u1 by A1;
 hence thesis by A3,Def1;
 end;
   now assume w,w1 '//' v1,v & v,v1 '//' u1,u & w,w1 '//' v2,u2;
 then w,w1 '//' v1,v & v1,v '//' u,u1 & w,w1 '//' v2,u2 by Def1;
 then w=w1 or v=v1 or v2,u2 '//' u,u1 by A1;
 hence thesis by A3,Def1;
 end;
 hence thesis by A2,A5,A6,A7,A8,A9,A10,A11,Def1;
 end;
 hence thesis by Def5,Def6;
end;

theorem
  AS is left_transitive implies AS is bach_transitive
proof
  (for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 ))) implies
(for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
  ((u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2)))
proof
A1:AS is left_transitive implies AS is right_transitive by Th17;

assume A2:for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
( (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 ));
let u,u1,u2,v,v1,v2,w,w1;
  assume A3:
  u,u1 '//' v,v1 & w,w1 '//' v,v1 & w,w1 '//' u2,v2;

A4:( v=v1 or w=w1 or u,u1 '//' u2,v2 or u,u1 '//' v2,u2)
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2)
  proof
  assume A5: v=v1 or w=w1 or u,u1 '//' u2,v2 or u,u1 '//' v2,u2;
    now assume A6:u,u1 '//' v2,u2 & u<>u1 & v<>v1 & w<>w1;
      then A7: v2,u2 '//' u,u1 or v2,u2 '//' u1,u by Def1;
     A8:now assume A9:u2,v2 '//' u1,u;
        then u2,v2 '//' u1,u & u1,u '//' v1,v & w1,w '//' v1,v by A3,Def1;
        then A10:u2,v2 '//' w1,w by A1,A2,A6,Def5,Def6;
          u2,v2 '//' u1,u & u1,u '//' u2,v2 & w,w1 '//' u2,v2 by A3,A6,A9,Def1;
        then A11:u2,v2 '//' w,w1 or u2=v2 by A1,A2,A6,Def5,Def6;
          now assume u2,v2 '//' w,w1;
        then w=w1 or u2=v2 by A10,Def1;
        hence thesis by A6;
        end;
        hence thesis by A11,Def1;
        end;
       now assume A12:u2,v2 '//' u,u1;
        then A13:u2,v2 '//' w,w1 by A1,A2,A3,A6,Def5,Def6;
          u2,v2 '//' u,u1 & u,u1 '//' v2,u2 & w1,w '//' v2,u2 by A3,A6,A12,Def1
;
        then A14:u2,v2 '//' w1,w or u2=v2 by A1,A2,A6,Def5,Def6;
          now assume u2,v2 '//' w1,w;
        then w=w1 or u2=v2 by A13,Def1;
        hence thesis by A6;
        end;
        hence thesis by A14,Def1;
        end;
      hence thesis by A7,A8,Def1;
      end;
 hence thesis by A5,Def1;
 end;
 A15: u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 implies thesis
   by A1,A2,Def5,Def6;
  A16:now assume u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w1,w;
     then u,u1 '//' v,v1 & v,v1 '//' w,w1 & v2,u2 '//' w,w1 by Def1;
     hence thesis by A1,A2,A4,Def5,Def6;
     end;
 A17: u,u1 '//' v,v1 & v,v1 '//' w1,w & u2,v2 '//' w1,w implies thesis
  by A1,A2,Def5,Def6;
    now assume u,u1 '//' v,v1 & v,v1 '//' w1,w & u2,v2 '//' w,w1;
     then u,u1 '//' v,v1 & v,v1 '//' w1,w & v2,u2 '//' w1,w by Def1;
     hence thesis by A1,A2,A4,Def5,Def6;
     end;
  hence thesis by A3,A15,A16,A17,Def1;
  end;
hence thesis by Def4,Def6;
end;

theorem
  AS is bach_transitive implies (AS is right_transitive iff
  (for u,u1,v,v1,u2,v2 holds
  ((u,u1 '//' u2,v2 & v,v1 '//' u2,v2 & u2<>v2) implies u,u1 // v,v1)))
  proof
  assume A1:AS is bach_transitive;
    (for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
  ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 ))) iff
  ((for u,u1,v,v1,u2,v2 holds
  ((u,u1 '//' u2,v2 & v,v1 '//' u2,v2 & u2<>v2) implies u,u1 // v,v1)))
  proof
  A2:(for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
  ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 ))) implies
  (for u,u1,v,v1,u2,v2 holds
  ((u,u1 '//' u2,v2 & v,v1 '//' u2,v2 & u2<>v2 ) implies u,u1 // v,v1))
  proof
  assume A3:for u,u1,u2,v,v1,v2,w,w1 being Element of AS
   holds (u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 );
  let u,u1,v,v1,u2,v2;
  assume A4:u,u1 '//' u2,v2 & v,v1 '//' u2,v2 & u2<>v2;
  consider w being Element of AS;
  consider w1 such that A5:w<>w1 & w,w1 '//' u,u1 by Def1;
  A6:now assume u<>u1;
  then w,w1 '//' v,v1 by A3,A4,A5;
  hence thesis by A5,Def3;
  end;
    now assume A7:u=u1;
  consider w being Element of AS;
  consider w1 such that A8:w<>w1 & w,w1 '//' v,v1 by Def1;
    w<>w1 & w,w1 '//' v,v1 & w,w1 '//' u,u by A8,Def1;
  hence thesis by A7,Def3;
  end;
  hence thesis by A6;
  end;
    (for u,u1,v,v1,u2,v2 holds
  ((u,u1 '//' u2,v2 & v,v1 '//' u2,v2 & u2<>v2) implies u,u1 // v,v1))
  implies (for u,u1,u2,v,v1,v2,w,w1 being Element of AS
  holds ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1 )
  implies (w=w1 or v=v1 or u,u1 '//' u2,v2 )))
  proof
  assume A9:  for u,u1,v,v1,u2,v2 holds
  (u,u1 '//' u2,v2 & v,v1 '//' u2,v2 & u2<>v2) implies u,u1 // v,v1;
  let u,u1,u2,v,v1,v2,w,w1;
  assume A10:u,u1 '//' v,v1 & v,v1 '//' w,w1 & u2,v2 '//' w,w1;
    now assume w<>w1 & v<>v1;
  then v,v1 // u2,v2 by A9,A10;
  then ex u3,v3 st u3<>v3 & u3,v3 '//' v,v1 & u3,v3 '//' u2,v2 by Def3;
  hence thesis by A1,A10,Def4;
  end;
  hence thesis;
  end;
  hence thesis by A2;
  end;
hence thesis by Def5;
end;

theorem
  AS is right_transitive & (AS is Euclidean_like or AS is Minkowskian_like)
implies AS is left_transitive
proof assume A1:AS is right_transitive;
   (for u,u1,v,v1 being Element of AS
 holds (u,u1 '//' v,v1 implies v,v1 '//' u,u1 ) or
 for u,u1,v,v1 being Element of AS
  holds (u,u1 '//' v,v1 implies v,v1 '//' u1,u )) implies
  (for u,u1,u2,v,v1,v2,w,w1 being Element of AS holds
  ((u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2 )
  implies (u=u1 or v=v1 or u2,v2 '//' w,w1 )))
  proof
   assume A2:
 for u,u1,v,v1 being Element of AS
   holds (u,u1 '//' v,v1 implies v,v1 '//' u,u1 ) or
 for u,u1,v,v1 being Element of AS
   holds (u,u1 '//' v,v1 implies v,v1 '//' u1,u );
let u,u1,u2,v,v1,v2,w,w1;
assume A3:u,u1 '//' v,v1 & v,v1 '//' w,w1 & u,u1 '//' u2,v2;
  A4:now assume A5:
 for u,u1,v,v1 being Element of AS
  holds (u,u1 '//' v,v1 implies v,v1 '//' u,u1 );
      now assume A6:u<>u1 & v<>v1;
          v,v1 '//' u,u1 & w,w1 '//' v,v1 & u2,v2 '//' u,u1 by A3,A5;
        then w,w1 '//' u2,v2 by A1,A6,Def5;
        hence thesis by A5;
        end;
  hence thesis;
  end;
    now assume A7:
 for u,u1,v,v1 being Element of AS
  holds (u,u1 '//' v,v1 implies v,v1 '//' u1,u );
      now assume A8:u<>u1 & v<>v1;
          v,v1 '//' u1,u & w,w1 '//' v1,v & u2,v2 '//' u1,u by A3,A7;
        then v,v1 '//' u1,u & w1,w '//' v,v1 & u2,v2 '//' u1,u by Def1;
        then w1,w '//' u2,v2 by A1,A8,Def5;
        hence thesis by A7;
        end;
  hence thesis;
  end;
hence thesis by A2,A4;
end;
hence thesis by Def6,Def7,Def8;
end;

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