let S be non empty RelStr ; :: thesis: 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 ; :: thesis: S --> (Top T) is infs-preserving
let X be Subset of S; :: according to WAYBEL_0:def 32 :: thesis: S --> (Top T) preserves_inf_of X
assume
ex_inf_of X,S
; :: according to WAYBEL_0:def 30 :: thesis: ( 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:
S --> (Top T) = the carrier of S --> (Top T)
;
A2:
(the carrier of S --> (Top T)) . (inf X) = Top T
by FUNCOP_1:13;
(S --> (Top T)) .: X c= {(Top T)}
by A1, FUNCOP_1:96;
then
( (S --> (Top T)) .: X = {(Top T)} or (S --> (Top T)) .: X = {} )
by ZFMISC_1:39;
hence
( ex_inf_of (S --> (Top T)) .: X,T & "/\" ((S --> (Top T)) .: X),T = (S --> (Top T)) . ("/\" X,S) )
by A1, A2, YELLOW_0:38, YELLOW_0:39, YELLOW_0:43; :: thesis: verum