let S be Subset of (TOP-REAL 2); for p, q being Point of (TOP-REAL 2) st p <> q & (LSeg p,q) \ {p,q} c= S holds
LSeg p,q c= Cl S
let p, q be Point of (TOP-REAL 2); ( p <> q & (LSeg p,q) \ {p,q} c= S implies LSeg p,q c= Cl S )
assume A1:
p <> q
; ( not (LSeg p,q) \ {p,q} c= S or LSeg p,q c= Cl S )
assume
(LSeg p,q) \ {p,q} c= S
; LSeg p,q c= Cl S
then
Cl ((LSeg p,q) \ {p,q}) c= Cl S
by PRE_TOPC:49;
hence
LSeg p,q c= Cl S
by A1, Th7; verum