let L be non empty RelStr ; for X being set st ( ex_inf_of X,L or ex_inf_of X /\ the carrier of L,L ) holds
"/\" X,L = "/\" (X /\ the carrier of L),L
let X be set ; ( ( ex_inf_of X,L or ex_inf_of X /\ the carrier of L,L ) implies "/\" X,L = "/\" (X /\ the carrier of L),L )
set Y = X /\ the carrier of L;
assume A1:
( ex_inf_of X,L or ex_inf_of X /\ the carrier of L,L )
; "/\" X,L = "/\" (X /\ the carrier of L),L
for x being Element of L holds
( x is_<=_than X iff x is_<=_than X /\ the carrier of L )
by Th5;
hence
"/\" X,L = "/\" (X /\ the carrier of L),L
by A1, Th49; verum