let AFP be AffinPlane; for a, b, p, p9, q, q9, x, y being Element of AFP
for K being Subset of AFP st a,b // K & not a in K & not x in K & AFP is Moufangian & p in K & p9 in K & p,a // p9,x & p,b // p9,y & x,y // K & q in K & q9 in K & q,a // q9,x holds
q,b // q9,y
let a, b, p, p9, q, q9, x, y be Element of AFP; for K being Subset of AFP st a,b // K & not a in K & not x in K & AFP is Moufangian & p in K & p9 in K & p,a // p9,x & p,b // p9,y & x,y // K & q in K & q9 in K & q,a // q9,x holds
q,b // q9,y
let K be Subset of AFP; ( a,b // K & not a in K & not x in K & AFP is Moufangian & p in K & p9 in K & p,a // p9,x & p,b // p9,y & x,y // K & q in K & q9 in K & q,a // q9,x implies q,b // q9,y )
assume that
A1:
a,b // K
and
A2:
not a in K
and
A3:
not x in K
and
A4:
AFP is Moufangian
and
A5:
p in K
and
A6:
p9 in K
and
A7:
p,a // p9,x
and
A8:
p,b // p9,y
and
A9:
x,y // K
and
A10:
q in K
and
A11:
q9 in K
and
A12:
q,a // q9,x
; q,b // q9,y
A13:
K is being_line
by A1, AFF_1:26;
A14:
now ( not a,x // K & a <> b implies q,b // q9,y )A15:
a,
q // x,
q9
by A12, AFF_1:4;
A16:
b,
p // y,
p9
by A8, AFF_1:4;
A17:
a,
p // x,
p9
by A7, AFF_1:4;
set A =
Line (
a,
x);
assume that A18:
not
a,
x // K
and A19:
a <> b
;
q,b // q9,y
a <> x
by A13, A18, AFF_1:33;
then A20:
Line (
a,
x) is
being_line
by AFF_1:def 3;
A21:
x in Line (
a,
x)
by AFF_1:15;
A22:
a in Line (
a,
x)
by AFF_1:15;
then consider o being
Element of
AFP such that A23:
o in Line (
a,
x)
and A24:
o in K
by A13, A18, A21, A20, AFF_1:40, AFF_1:58;
A25:
LIN o,
a,
x
by A22, A21, A20, A23, AFF_1:21;
K is
being_line
by A1, AFF_1:26;
then
a,
b // x,
y
by A1, A9, AFF_1:31;
then
LIN o,
b,
y
by A1, A2, A4, A5, A6, A19, A24, A25, A17, A16, Lm3, AFF_1:26;
then
b,
q // y,
q9
by A1, A2, A4, A9, A10, A11, A13, A24, A25, A15, Lm2;
hence
q,
b // q9,
y
by AFF_1:4;
verum end;
A26:
now ( a,x // K & a <> b & p <> q implies q,b // q9,y )set M =
Line (
a,
b);
assume that A27:
a,
x // K
and A28:
a <> b
and A29:
p <> q
;
q,b // q9,yA30:
Line (
a,
b) is
being_line
by A28, AFF_1:def 3;
K is
being_line
by A1, AFF_1:26;
then
a,
b // a,
x
by A1, A27, AFF_1:31;
then
LIN a,
b,
x
by AFF_1:def 1;
then A31:
x in Line (
a,
b)
by AFF_1:def 2;
A32:
b in Line (
a,
b)
by AFF_1:15;
A33:
a in Line (
a,
b)
by AFF_1:15;
A34:
Line (
a,
b)
// K
by A1, A28, AFF_1:def 5;
then
x,
y // Line (
a,
b)
by A9, AFF_1:43;
then
y in Line (
a,
b)
by A30, A31, AFF_1:23;
hence
q,
b // q9,
y
by A4, A5, A6, A7, A8, A10, A11, A12, A28, A29, A33, A32, A34, A31, Th7;
verum end;
A35:
( a = b implies x = y )
proof
set M =
Line (
x,
y);
A36:
x in Line (
x,
y)
by AFF_1:15;
assume
a = b
;
x = y
then
p9,
x // p9,
y
by A2, A5, A7, A8, AFF_1:5;
then
LIN p9,
x,
y
by AFF_1:def 1;
then
LIN x,
y,
p9
by AFF_1:6;
then A37:
p9 in Line (
x,
y)
by AFF_1:def 2;
assume
x <> y
;
contradiction
then
Line (
x,
y)
// K
by A9, AFF_1:def 5;
hence
contradiction
by A3, A6, A36, A37, AFF_1:45;
verum
end;
now ( p = q implies q,b // q9,y )assume A38:
p = q
;
q,b // q9,y
p9 = q9
proof
p9,
x // q9,
x
by A2, A5, A7, A12, A38, AFF_1:5;
then
x,
p9 // x,
q9
by AFF_1:4;
then
LIN x,
p9,
q9
by AFF_1:def 1;
then A39:
LIN p9,
q9,
x
by AFF_1:6;
assume
p9 <> q9
;
contradiction
hence
contradiction
by A1, A3, A6, A11, A39, AFF_1:25, AFF_1:26;
verum
end; hence
q,
b // q9,
y
by A8, A38;
verum end;
hence
q,b // q9,y
by A12, A35, A14, A26; verum