let P be Element of BK_model ; ex P1, P2 being Element of absolute st
( P1 <> P2 & P1,P,P2 are_collinear )
consider Q being Element of BK_model such that
A1:
P <> Q
by Th11;
consider P1, P2 being Element of absolute such that
A2:
P1 <> P2
and
A3:
P,Q,P1 are_collinear
and
A4:
P,Q,P2 are_collinear
by A1, BKMODEL2:20;
take
P1
; ex P2 being Element of absolute st
( P1 <> P2 & P1,P,P2 are_collinear )
take
P2
; ( P1 <> P2 & P1,P,P2 are_collinear )
P,P1,P2 are_collinear
by A1, A3, A4, COLLSP:6;
hence
( P1 <> P2 & P1,P,P2 are_collinear )
by A2, COLLSP:4; verum