let X be OrtAfPl; :: thesis: ( X is satisfying_MH1 implies X is satisfying_OSCH )
assume A1: X is satisfying_MH1 ; :: 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 that
A2: M _|_ N and
A3: a1 in M and
A4: a3 in M and
A5: b1 in M and
A6: b3 in M and
A7: a2 in N and
A8: a4 in N and
A9: b2 in N and
A10: b4 in N and
A11: not a4 in M and
A12: not a2 in M and
A13: not b2 in M and
A14: not b4 in M and
A15: not a1 in N and
A16: not a3 in N and
A17: not b1 in N and
not b3 in N and
A18: a3,a2 // b3,b2 and
A19: a2,a1 // b2,b1 and
A20: a1,a4 // b1,b4 ; :: thesis: a3,a4 // b3,b4
reconsider M' = M, N' = N as Subset of (Af X) by ANALMETR:57;
N is being_line by A2, ANALMETR:62;
then A21: N' is being_line by ANALMETR:58;
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;
M is being_line by A2, ANALMETR:62;
then A22: M' is being_line by ANALMETR:58;
not M' // N'
proof end;
then ex o' being Element of (Af X) st
( o' in M' & o' in N' ) by A22, A21, AFF_1:72;
then consider o being Element of X such that
A23: o in M and
A24: o in N ;
reconsider o' = o as Element of (Af X) by ANALMETR:47;
A25: now
assume A26: b2 <> b4 ; :: thesis: a3,a4 // b3,b4
A27: now
consider e1' being Element of (Af X) such that
A28: o' <> e1' and
A29: e1' in M' by A22, AFF_1:32;
reconsider e1 = e1' as Element of X by ANALMETR:47;
ex d4' being Element of (Af X) st
( o' <> d4' & d4' in N' ) by A21, AFF_1:32;
then consider d4 being Element of X such that
A30: d4 in N and
A31: d4 <> o ;
reconsider d4' = d4 as Element of (Af X) by ANALMETR:47;
consider e2 being Element of X such that
A32: a1,a4 _|_ d4,e2 and
A33: e2 <> d4 by ANALMETR:51;
reconsider e2' = e2 as Element of (Af X) by ANALMETR:47;
assume A34: b1 <> b3 ; :: thesis: a3,a4 // b3,b4
not o',e1' // d4',e2'
proof end;
then consider d1' being Element of (Af X) such that
A39: LIN o',e1',d1' and
A40: LIN d4',e2',d1' by AFF_1:74;
reconsider d1 = d1' as Element of X by ANALMETR:47;
consider e1' being Element of (Af X) such that
A41: o' <> e1' and
A42: e1' in N' by A21, AFF_1:32;
A43: d1 in M by A22, A23, A28, A29, A39, AFF_1:39;
LIN d4,e2,d1 by A40, ANALMETR:55;
then d4,e2 // d4,d1 by ANALMETR:def 11;
then A44: d1,d4 // d4,e2 by ANALMETR:81;
then a1,a4 _|_ d1,d4 by A32, A33, ANALMETR:84;
then A45: b1,b4 _|_ d1,d4 by A3, A11, A20, ANALMETR:84;
reconsider e1 = e1' as Element of X by ANALMETR:47;
consider e2 being Element of X such that
A46: a2,a1 _|_ d1,e2 and
A47: e2 <> d1 by ANALMETR:51;
reconsider e2' = e2 as Element of (Af X) by ANALMETR:47;
not o',e1' // e2',d1'
proof end;
then consider d2' being Element of (Af X) such that
A53: LIN o',e1',d2' and
A54: LIN e2',d1',d2' by AFF_1:74;
reconsider d2 = d2' as Element of X by ANALMETR:47;
A55: d2 in N by A21, A24, A41, A42, A53, AFF_1:39;
LIN d1',d2',e2' by A54, AFF_1:15;
then LIN d1,d2,e2 by ANALMETR:55;
then d1,d2 // d1,e2 by ANALMETR:def 11;
then A56: d2,d1 // e2,d1 by ANALMETR:81;
A57: a2,a1 _|_ e2,d1 by A46, ANALMETR:83;
then A58: a2,a1 _|_ d2,d1 by A47, A56, ANALMETR:84;
consider e1' being Element of (Af X) such that
A59: o' <> e1' and
A60: e1' in M' by A22, AFF_1:32;
reconsider e1 = e1' as Element of X by ANALMETR:47;
consider e2 being Element of X such that
A61: a3,a2 _|_ d2,e2 and
A62: e2 <> d2 by ANALMETR:51;
reconsider e2' = e2 as Element of (Af X) by ANALMETR:47;
not o',e1' // e2',d2'
proof end;
then consider d3' being Element of (Af X) such that
A65: LIN o',e1',d3' and
A66: LIN e2',d2',d3' by AFF_1:74;
reconsider d3 = d3' as Element of X by ANALMETR:47;
A67: d3 in M by A22, A23, A59, A60, A65, AFF_1:39;
then A68: d3 <> d4 by A2, A22, A21, A23, A24, A30, A31, AFF_1:30;
a2,a1 _|_ d2,d1 by A47, A56, A57, ANALMETR:84;
then A69: b2,b1 _|_ d2,d1 by A3, A12, A19, ANALMETR:84;
LIN d2',d3',e2' by A66, AFF_1:15;
then LIN d2,d3,e2 by ANALMETR:55;
then d2,d3 // d2,e2 by ANALMETR:def 11;
then d3,d2 // d2,e2 by ANALMETR:81;
then A70: a3,a2 _|_ d3,d2 by A61, A62, ANALMETR:84;
then b3,b2 _|_ d3,d2 by A4, A12, A18, ANALMETR:84;
then A71: b3,b4 _|_ d3,d4 by A1, A2, A5, A6, A9, A10, A13, A14, A30, A43, A55, A67, A45, A69, Def3;
a1,a4 _|_ d1,d4 by A32, A33, A44, ANALMETR:84;
then a3,a4 _|_ d3,d4 by A1, A2, A3, A4, A7, A8, A11, A12, A30, A43, A55, A58, A70, A67, Def3;
hence a3,a4 // b3,b4 by A68, A71, ANALMETR:85; :: thesis: verum
end;
now
A72: not LIN o',a2',a1'
proof
assume LIN o',a2',a1' ; :: thesis: contradiction
then o',a2' // o',a1' by AFF_1:def 1;
hence contradiction by A7, A12, A15, A21, A23, A24, AFF_1:62; :: thesis: verum
end;
A73: LIN o',a1',a3' by A3, A4, A22, A23, AFF_1:33;
assume A74: b1 = b3 ; :: thesis: a3,a4 // b3,b4
then a2,a3 // b2,b1 by A18, ANALMETR:81;
then A75: a2',a3' // b2',b1' by ANALMETR:48;
a2',a1' // b2',b1' by A19, ANALMETR:48;
then a2',a1' // a2',a3' by A5, A13, A75, AFF_1:14;
hence a3,a4 // b3,b4 by A20, A74, A72, A73, AFF_1:23; :: thesis: verum
end;
hence a3,a4 // b3,b4 by A27; :: thesis: verum
end;
now
A76: not LIN o',a1',a4'
proof
assume LIN o',a1',a4' ; :: thesis: contradiction
then ex A' being Subset of (Af X) st
( A' is being_line & o' in A' & a1' in A' & a4' in A' ) by AFF_1:33;
hence contradiction by A3, A11, A15, A22, A23, A24, AFF_1:30; :: thesis: verum
end;
assume A77: b2 = b4 ; :: thesis: a3,a4 // b3,b4
b1,b2 // a1,a2 by A19, ANALMETR:81;
then a1,a4 // a1,a2 by A5, A13, A20, A77, ANALMETR:82;
then A78: a1',a4' // a1',a2' by ANALMETR:48;
LIN o',a4',a2' by A7, A8, A21, A24, AFF_1:33;
hence a3,a4 // b3,b4 by A18, A77, A78, A76, AFF_1:23; :: thesis: verum
end;
hence a3,a4 // b3,b4 by A25; :: thesis: verum