theorem
for
AS being non
empty AffinStruct holds
( ( ex
a,
b being
Element of
AS st
a <> b & ( for
a,
b,
c,
d,
p,
q,
r,
s being
Element of
AS holds
(
a,
b // c,
c & (
a,
b // b,
a implies
a = b ) & (
a <> b &
a,
b // p,
q &
a,
b // r,
s implies
p,
q // r,
s ) & (
a,
b // c,
d implies
b,
a // d,
c ) & (
a,
b // b,
c implies
a,
b // a,
c ) & ( not
a,
b // a,
c or
a,
b // b,
c or
a,
c // c,
b ) ) ) & ex
a,
b,
c,
d being
Element of
AS st
( not
a,
b // c,
d & not
a,
b // d,
c ) & ( for
a,
b,
c being
Element of
AS ex
d being
Element of
AS st
(
a,
b // c,
d &
a,
c // b,
d &
b <> d ) ) & ( for
p,
a,
b,
c being
Element of
AS st
p <> b &
b,
p // p,
c holds
ex
d being
Element of
AS st
(
a,
p // p,
d &
a,
b // c,
d ) ) ) iff
AS is
OAffinSpace )
by Def5, STRUCT_0:def 10;