let X be OrtAfPl; :: thesis: ( X is satisfying_MH2 implies X is satisfying_OSCH )
assume A1: X is satisfying_MH2 ; :: thesis: X is satisfying_OSCH
let a1 be Element of X; :: according to CONMETR:def 7 :: thesis: for a2, a3, a4, b1, b2, b3, b4 being Element of X
for M, N being Subset of X st M _|_ N & a1 in M & a3 in M & b1 in M & b3 in M & a2 in N & a4 in N & b2 in N & b4 in N & not a4 in M & not a2 in M & not b2 in M & not b4 in M & not a1 in N & not a3 in N & not b1 in N & not b3 in N & a3,a2 // b3,b2 & a2,a1 // b2,b1 & a1,a4 // b1,b4 holds
a3,a4 // b3,b4

let a2, a3, a4, b1, b2, b3, b4 be Element of X; :: thesis: for M, N being Subset of X st M _|_ N & a1 in M & a3 in M & b1 in M & b3 in M & a2 in N & a4 in N & b2 in N & b4 in N & not a4 in M & not a2 in M & not b2 in M & not b4 in M & not a1 in N & not a3 in N & not b1 in N & not b3 in N & a3,a2 // b3,b2 & a2,a1 // b2,b1 & a1,a4 // b1,b4 holds
a3,a4 // b3,b4

let M, N be Subset of X; :: thesis: ( M _|_ N & a1 in M & a3 in M & b1 in M & b3 in M & a2 in N & a4 in N & b2 in N & b4 in N & not a4 in M & not a2 in M & not b2 in M & not b4 in M & not a1 in N & not a3 in N & not b1 in N & not b3 in N & a3,a2 // b3,b2 & a2,a1 // b2,b1 & a1,a4 // b1,b4 implies a3,a4 // b3,b4 )
assume A2: ( M _|_ N & a1 in M & a3 in M & b1 in M & b3 in M & a2 in N & a4 in N & b2 in N & b4 in N & not a4 in M & not a2 in M & not b2 in M & not b4 in M & not a1 in N & not a3 in N & not b1 in N & not b3 in N & a3,a2 // b3,b2 & a2,a1 // b2,b1 & a1,a4 // b1,b4 ) ; :: thesis: a3,a4 // b3,b4
then A3: ( M is being_line & N is being_line ) by ANALMETR:62;
reconsider b4' = b4, b1' = b1, b2' = b2, b3' = b3, a1' = a1, a2' = a2, a3' = a3, a4' = a4 as Element of (Af X) by ANALMETR:47;
reconsider M' = M, N' = N as Subset of (Af X) by ANALMETR:57;
A4: ( M' is being_line & N' is being_line ) by A3, ANALMETR:58;
not M' // N'
proof end;
then ex o' being Element of (Af X) st
( o' in M' & o' in N' ) by A4, AFF_1:72;
then consider o being Element of X such that
A5: ( o in M & o in N ) ;
reconsider o' = o as Element of (Af X) by ANALMETR:47;
A6: now
assume A7: b2 = b4 ; :: thesis: a3,a4 // b3,b4
A8: not LIN o',a1',a2' by A2, A4, A5, AFF_1:39;
A9: LIN o',a2',a4'
proof
N' // N' by A4, AFF_1:55;
then o',a2' // o',a4' by A2, A5, AFF_1:53;
hence LIN o',a2',a4' by AFF_1:def 1; :: thesis: verum
end;
a1',a2' // a1',a4'
proof end;
hence a3,a4 // b3,b4 by A2, A7, A8, A9, AFF_1:23; :: thesis: verum
end;
now
assume A10: b2 <> b4 ; :: thesis: a3,a4 // b3,b4
A11: now
assume A12: b1 = b3 ; :: thesis: a3,a4 // b3,b4
A13: not LIN o',a2',a1' by A2, A4, A5, AFF_1:39;
A14: LIN o',a1',a3'
proof
M' // M' by A4, AFF_1:55;
then o',a1' // o',a3' by A2, A5, AFF_1:53;
hence LIN o',a1',a3' by AFF_1:def 1; :: thesis: verum
end;
a2',a1' // a2',a3' hence a3,a4 // b3,b4 by A2, A12, A13, A14, AFF_1:23; :: thesis: verum
end;
now
assume A15: b1 <> b3 ; :: thesis: a3,a4 // b3,b4
A16: ( a1 <> a3 & a2 <> a4 )
proof
assume ( a1 = a3 or a2 = a4 ) ; :: thesis: contradiction
then ( a2,a1 // b3,b2 or a1,a4 // b2,b1 ) by A2, ANALMETR:81;
then ( b3,b2 // b2,b1 or b2,b1 // b1,b4 ) by A2, ANALMETR:82;
then ( b2,b3 // b2,b1 or b1,b2 // b1,b4 ) by ANALMETR:81;
then ( LIN b2,b3,b1 or LIN b1,b2,b4 ) by ANALMETR:def 11;
then ( LIN b2',b3',b1' or LIN b1',b2',b4' ) by ANALMETR:55;
then ( LIN b1',b3',b2' or LIN b2',b4',b1' ) by AFF_1:15;
hence contradiction by A2, A4, A10, A15, AFF_1:39; :: thesis: verum
end;
consider d3' being Element of (Af X) such that
A17: ( o' <> d3' & d3' in N' ) by A4, AFF_1:32;
consider d3 being Element of X such that
A18: ( d3 in N & d3 <> o ) by A17;
reconsider d3' = d3 as Element of (Af X) by ANALMETR:47;
consider e1 being Element of X such that
A19: ( a3,a1 // a3,e1 & a3 <> e1 ) by ANALMETR:51;
consider e2 being Element of X such that
A20: ( a3,a2 _|_ d3,e2 & d3 <> e2 ) by ANALMETR:def 10;
reconsider e1' = e1, e2' = e2 as Element of (Af X) by ANALMETR:47;
not a3',e1' // d3',e2' then consider d2' being Element of (Af X) such that
A22: ( LIN a3',e1',d2' & LIN d3',e2',d2' ) by AFF_1:74;
reconsider d2 = d2' as Element of X by ANALMETR:47;
A23: d2 in M
proof
LIN a3,e1,d2 by A22, ANALMETR:55;
then a3,e1 // a3,d2 by ANALMETR:def 11;
then a3,a1 // a3,d2 by A19, ANALMETR:82;
then LIN a3,a1,d2 by ANALMETR:def 11;
then LIN a3',a1',d2' by ANALMETR:55;
hence d2 in M by A2, A4, A16, AFF_1:39; :: thesis: verum
end;
a3,a2 _|_ d3,d2 then consider d2 being Element of X such that
A24: ( d2 in M & a3,a2 _|_ d3,d2 ) by A23;
reconsider d2' = d2 as Element of (Af X) by ANALMETR:47;
consider e1 being Element of X such that
A25: ( a2,a4 // a2,e1 & a2 <> e1 ) by ANALMETR:51;
consider e2 being Element of X such that
A26: ( a2,a1 _|_ d2,e2 & d2 <> e2 ) by ANALMETR:def 10;
reconsider e1' = e1, e2' = e2 as Element of (Af X) by ANALMETR:47;
not a2',e1' // d2',e2' then consider d1' being Element of (Af X) such that
A28: ( LIN a2',e1',d1' & LIN d2',e2',d1' ) by AFF_1:74;
reconsider d1 = d1' as Element of X by ANALMETR:47;
A29: d1 in N
proof
LIN a2,e1,d1 by A28, ANALMETR:55;
then a2,e1 // a2,d1 by ANALMETR:def 11;
then a2,a4 // a2,d1 by A25, ANALMETR:82;
then LIN a2,a4,d1 by ANALMETR:def 11;
then LIN a2',a4',d1' by ANALMETR:55;
hence d1 in N by A2, A4, A16, AFF_1:39; :: thesis: verum
end;
A30: a2,a1 _|_ d2,d1 consider e1 being Element of X such that
A31: ( a1,a3 // a1,e1 & a1 <> e1 ) by ANALMETR:51;
consider e2 being Element of X such that
A32: ( a1,a4 _|_ d1,e2 & d1 <> e2 ) by ANALMETR:51;
reconsider e1' = e1, e2' = e2 as Element of (Af X) by ANALMETR:47;
not a1',e1' // d1',e2' then consider d4' being Element of (Af X) such that
A34: ( LIN a1',e1',d4' & LIN d1',e2',d4' ) by AFF_1:74;
reconsider d4 = d4' as Element of X by ANALMETR:47;
A35: d4 in M
proof
LIN a1,e1,d4 by A34, ANALMETR:55;
then a1,e1 // a1,d4 by ANALMETR:def 11;
then a1,a3 // a1,d4 by A31, ANALMETR:82;
then LIN a1,a3,d4 by ANALMETR:def 11;
then LIN a1',a3',d4' by ANALMETR:55;
hence d4 in M by A2, A4, A16, AFF_1:39; :: thesis: verum
end;
A36: a1,a4 _|_ d1,d4 then A37: a3,a4 _|_ d3,d4 by A1, A2, A18, A24, A29, A30, A35, Def4;
A38: b3,b2 _|_ d3,d2 by A2, A24, ANALMETR:84;
A39: b2,b1 _|_ d2,d1 by A2, A30, ANALMETR:84;
b1,b4 _|_ d1,d4 by A2, A36, ANALMETR:84;
then A40: b3,b4 _|_ d3,d4 by A1, A2, A18, A24, A29, A35, A38, A39, Def4;
d3 <> d4 by A2, A4, A5, A18, A35, AFF_1:30;
hence a3,a4 // b3,b4 by A37, A40, ANALMETR:85; :: thesis: verum
end;
hence a3,a4 // b3,b4 by A11; :: thesis: verum
end;
hence a3,a4 // b3,b4 by A6; :: thesis: verum