let f be FinSequence of (TOP-REAL 2); for p, q being Point of (TOP-REAL 2) st f is being_S-Seq & p in L~ f & q in L~ f & p <> q holds
B_Cut (f,p,q) is being_S-Seq
let p, q be Point of (TOP-REAL 2); ( f is being_S-Seq & p in L~ f & q in L~ f & p <> q implies B_Cut (f,p,q) is being_S-Seq )
assume that
A1:
f is being_S-Seq
and
A2:
p in L~ f
and
A3:
q in L~ f
and
A4:
p <> q
; B_Cut (f,p,q) is being_S-Seq
B_Cut (f,p,q) is_S-Seq_joining p,q
by A1, A2, A3, A4, Th36;
hence
B_Cut (f,p,q) is being_S-Seq
; verum