let CLSP be proper CollSp; for p, q being Point of CLSP
for P being LINE of CLSP st p <> q & p in P & q in P holds
Line p,q = P
let p, q be Point of CLSP; for P being LINE of CLSP st p <> q & p in P & q in P holds
Line p,q = P
let P be LINE of CLSP; ( p <> q & p in P & q in P implies Line p,q = P )
assume that
A1:
p <> q
and
A2:
( p in P & q in P )
; Line p,q = P
reconsider Q = Line p,q as LINE of CLSP by A1, Def7;
Q c= P
by A1, A2, Th27;
hence
Line p,q = P
by Th26; verum