let S be non empty RelStr ; for T being non empty reflexive antisymmetric upper-bounded RelStr holds S --> (Top T) is infs-preserving
let T be non empty reflexive antisymmetric upper-bounded RelStr ; S --> (Top T) is infs-preserving
let X be Subset of S; WAYBEL_0:def 32 S --> (Top T) preserves_inf_of X
assume
ex_inf_of X,S
; WAYBEL_0:def 30 ( ex_inf_of (S --> (Top T)) .: X,T & "/\" (((S --> (Top T)) .: X),T) = (S --> (Top T)) . ("/\" (X,S)) )
set t = Top T;
set f = the carrier of S --> (Top T);
A1:
( the carrier of S --> (Top T)) . (inf X) = Top T
by FUNCOP_1:7;
(S --> (Top T)) .: X c= {(Top T)}
by FUNCOP_1:81;
then
( (S --> (Top T)) .: X = {(Top T)} or (S --> (Top T)) .: X = {} )
by ZFMISC_1:33;
hence
( ex_inf_of (S --> (Top T)) .: X,T & "/\" (((S --> (Top T)) .: X),T) = (S --> (Top T)) . ("/\" (X,S)) )
by A1, YELLOW_0:38, YELLOW_0:39, YELLOW_0:43; verum