for S being OAffinSpace
for AS being non empty AffinStruct st AS = Lambda S holds
for a, b, c, d being Element of S
for a9, b9, c9, d9 being Element of AS st a = a9 & b = b9 & c = c9 & d = d9 holds
( a9,b9 // c9,d9 iff a,b '||' c,d )