let AP be AffinPlane; ( AP is Moufangian implies AP is satisfying_TDES_1 )
assume A1:
AP is Moufangian
; AP is satisfying_TDES_1
thus
AP is satisfying_TDES_1
verumproof
let K be
Subset of ;
AFF_2:def 8 for o, a, b, c, a', b', c' being Element of st K is being_line & o in K & c in K & c' in K & not a in K & o <> c & a <> b & LIN o,a,a' & a,b // a',b' & b,c // b',c' & a,c // a',c' & a,b // K holds
LIN o,b,b'let o,
a,
b,
c,
a',
b',
c' be
Element of ;
( K is being_line & o in K & c in K & c' in K & not a in K & o <> c & a <> b & LIN o,a,a' & a,b // a',b' & b,c // b',c' & a,c // a',c' & a,b // K implies LIN o,b,b' )
assume that A2:
K is
being_line
and A3:
o in K
and A4:
c in K
and A5:
c' in K
and A6:
not
a in K
and A7:
o <> c
and A8:
a <> b
and A9:
LIN o,
a,
a'
and A10:
a,
b // a',
b'
and A11:
b,
c // b',
c'
and A12:
a,
c // a',
c'
and A13:
a,
b // K
;
LIN o,b,b'
consider P being
Subset of
such that A14:
a' in P
and A15:
K // P
by A2, AFF_1:63;
A16:
P is
being_line
by A15, AFF_1:50;
set A =
Line o,
b;
set C =
Line o,
a;
A17:
(
o in Line o,
b &
b in Line o,
b )
by AFF_1:26;
assume A18:
not
LIN o,
b,
b'
;
contradiction
then
o <> b
by AFF_1:16;
then A19:
Line o,
b is
being_line
by AFF_1:def 3;
A20:
not
b in K
by A6, A13, AFF_1:49;
not
Line o,
b // P
then consider x being
Element of
such that A21:
x in Line o,
b
and A22:
x in P
by A19, A16, AFF_1:72;
A23:
(
o in Line o,
a &
a in Line o,
a )
by AFF_1:26;
A24:
LIN o,
b,
x
by A19, A17, A21, AFF_1:33;
a,
b // P
by A13, A15, AFF_1:57;
then
a',
b' // P
by A8, A10, AFF_1:46;
then A25:
b' in P
by A14, A16, AFF_1:37;
then A26:
LIN b',
x,
b'
by A16, A22, AFF_1:33;
A27:
Line o,
a is
being_line
by A3, A6, AFF_1:def 3;
then A28:
a' in Line o,
a
by A3, A6, A9, A23, AFF_1:39;
A29:
b' <> c'
proof
A30:
a',
c' // c,
a
by A12, AFF_1:13;
assume A31:
b' = c'
;
contradiction
then
P = K
by A5, A15, A25, AFF_1:59;
then
a' = o
by A2, A3, A6, A27, A23, A28, A14, AFF_1:30;
then
b' = o
by A2, A3, A4, A5, A6, A31, A30, AFF_1:62;
hence
contradiction
by A18, AFF_1:16;
verum
end;
A32:
b <> c
by A4, A6, A13, AFF_1:49;
a',
x // K
by A14, A15, A22, AFF_1:54;
then
a,
b // a',
x
by A2, A13, AFF_1:45;
then
b,
c // x,
c'
by A1, A2, A3, A4, A5, A6, A7, A8, A9, A12, A13, A24, Def7;
then
b',
c' // x,
c'
by A11, A32, AFF_1:14;
then
c',
b' // c',
x
by AFF_1:13;
then
LIN c',
b',
x
by AFF_1:def 1;
then A33:
LIN b',
x,
c'
by AFF_1:15;
A34:
a' <> b'
proof
assume A35:
a' = b'
;
contradiction
(
a,
c // b,
c or
a' = c' )
by A11, A12, A35, AFF_1:14;
then
c,
a // c,
b
by A36, AFF_1:13;
then
LIN c,
a,
b
by AFF_1:def 1;
then
LIN a,
c,
b
by AFF_1:15;
then
a,
c // a,
b
by AFF_1:def 1;
then
a,
b // a,
c
by AFF_1:13;
then
a,
c // K
by A8, A13, AFF_1:46;
then
c,
a // K
by AFF_1:48;
hence
contradiction
by A2, A4, A6, AFF_1:37;
verum
end;
LIN b',
x,
a'
by A14, A16, A22, A25, AFF_1:33;
then
LIN b',
c',
a'
by A18, A24, A33, A26, AFF_1:17;
then
b',
c' // b',
a'
by AFF_1:def 1;
then
b',
c' // a',
b'
by AFF_1:13;
then
b,
c // a',
b'
by A11, A29, AFF_1:14;
then
a,
b // b,
c
by A10, A34, AFF_1:14;
then
b,
c // K
by A8, A13, AFF_1:46;
then
c,
b // K
by AFF_1:48;
hence
contradiction
by A2, A4, A20, AFF_1:37;
verum
end;