let C be complete Lattice; for a being Element of C
for X being set st a in X & a is_less_than X holds
"/\" (X,C) = a
let a be Element of C; for X being set st a in X & a is_less_than X holds
"/\" (X,C) = a
let X be set ; ( a in X & a is_less_than X implies "/\" (X,C) = a )
assume that
A1:
a in X
and
A2:
a is_less_than X
; "/\" (X,C) = a
A3:
"/\" (X,C) [= a
by A1, Th38;
a [= "/\" (X,C)
by A2, Th39;
hence
"/\" (X,C) = a
by A3, LATTICES:8; verum