let V be RealLinearSpace; :: thesis: for x, y being VECTOR of V st Gen x,y holds
( ( for u, u1, v, v1, w being Element of (CMSpace V,x,y) holds
( u,u '//' v,w & u,v '//' w,w & ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) ) ) & ( for u, v, w being Element of (CMSpace V,x,y) 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) ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 ) ) )

let x, y be VECTOR of V; :: thesis: ( Gen x,y implies ( ( for u, u1, v, v1, w being Element of (CMSpace V,x,y) holds
( u,u '//' v,w & u,v '//' w,w & ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) ) ) & ( for u, v, w being Element of (CMSpace V,x,y) 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) ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 ) ) ) )

assume A1: Gen x,y ; :: thesis: ( ( for u, u1, v, v1, w being Element of (CMSpace V,x,y) holds
( u,u '//' v,w & u,v '//' w,w & ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) ) ) & ( for u, v, w being Element of (CMSpace V,x,y) 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) ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 ) ) )

set S = CMSpace V,x,y;
A2: CMSpace V,x,y = AffinStruct(# the carrier of V,(CORTM V,x,y) #) by ANALORT:def 8;
thus for u, u1, v, v1, w being Element of (CMSpace V,x,y) holds
( u,u '//' v,w & u,v '//' w,w & ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) ) :: thesis: ( ( for u, v, w being Element of (CMSpace V,x,y) 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) ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 ) ) )
proof
let u, u1, v, v1, w be Element of (CMSpace V,x,y); :: thesis: ( u,u '//' v,w & u,v '//' w,w & ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) )
reconsider u' = u, v' = v, w' = w, u1' = u1, v1' = v1 as Element of V by A2;
thus u,u '//' v,w :: thesis: ( u,v '//' w,w & ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) )
proof end;
thus u,v '//' w,w :: thesis: ( ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) & ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) )
proof end;
thus ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) :: thesis: ( ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies 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 ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) )
proof
( u',v',u1',v1' are_COrtm_wrt x,y & u',v',v1',u1' are_COrtm_wrt x,y & not u' = v' implies u1' = v1' ) by A1, ANALORT:31;
hence ( u,v '//' u1,v1 & u,v '//' v1,u1 & not u = v implies u1 = v1 ) by ANALORT:57; :: thesis: verum
end;
thus ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies u,v '//' w,v1 ) :: thesis: ( ( u,v '//' u1,v1 implies v,u '//' v1,u1 ) & ( u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) )
proof
( u',v',u1',v1' are_COrtm_wrt x,y & u',v',u1',w' are_COrtm_wrt x,y & not u',v',v1',w' are_COrtm_wrt x,y implies u',v',w',v1' are_COrtm_wrt x,y ) by A1, ANALORT:33;
hence ( u,v '//' u1,v1 & u,v '//' u1,w & not u,v '//' v1,w implies u,v '//' w,v1 ) by ANALORT:57; :: thesis: verum
end;
thus ( u,v '//' u1,v1 implies v,u '//' v1,u1 ) :: thesis: ( ( u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w ) & ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) )
proof
( u',v',u1',v1' are_COrtm_wrt x,y implies v',u',v1',u1' are_COrtm_wrt x,y ) by ANALORT:35;
hence ( u,v '//' u1,v1 implies v,u '//' v1,u1 ) by ANALORT:57; :: thesis: verum
end;
thus ( u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w ) :: thesis: ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u )
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 ( u,v '//' u1,v1 & u,v '//' v1,w implies u,v '//' u1,w ) by ANALORT:57; :: thesis: verum
end;
thus ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) :: thesis: verum
proof
( not u',u1',v',v1' are_COrtm_wrt x,y or v',v1',u',u1' are_COrtm_wrt x,y or v',v1',u1',u' are_COrtm_wrt x,y ) by A1, ANALORT:19;
hence ( not u,u1 '//' v,v1 or v,v1 '//' u,u1 or v,v1 '//' u1,u ) by ANALORT:57; :: thesis: verum
end;
thus verum ; :: thesis: verum
end;
thus for u, v, w being Element of (CMSpace V,x,y) ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & w,u1 '//' u,v ) :: thesis: for u, v, w being Element of (CMSpace V,x,y) ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 )
proof
let u, v, w be Element of (CMSpace V,x,y); :: thesis: ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & w,u1 '//' u,v )

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 (CMSpace V,x,y) by A2;
( w <> u1 & w,u1 '//' u,v ) by A3, ANALORT:57;
hence ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & w,u1 '//' u,v ) ; :: thesis: verum
end;
let u, v, w be Element of (CMSpace V,x,y); :: thesis: ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 )

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 (CMSpace V,x,y) by A2;
( w <> u1 & u,v '//' w,u1 ) by A4, ANALORT:57;
hence ex u1 being Element of (CMSpace V,x,y) st
( w <> u1 & u,v '//' w,u1 ) ; :: thesis: verum