let T be complete LATTICE; :: thesis: for S being non empty full sups-inheriting SubRelStr of T holds incl S,T is sups-preserving
let S be non empty full sups-inheriting SubRelStr of T; :: thesis: incl S,T is sups-preserving
set f = incl S,T;
let X be Subset of S; :: according to WAYBEL_0:def 33 :: thesis: incl S,T preserves_sup_of X
assume
ex_sup_of X,S
; :: according to WAYBEL_0:def 31 :: thesis: ( ex_sup_of (incl S,T) .: X,T & "\/" ((incl S,T) .: X),T = (incl S,T) . ("\/" X,S) )
thus
ex_sup_of (incl S,T) .: X,T
by YELLOW_0:17; :: thesis: "\/" ((incl S,T) .: X),T = (incl S,T) . ("\/" X,S)
the carrier of S c= the carrier of T
by YELLOW_0:def 13;
then
incl S,T = id the carrier of S
by YELLOW_9:def 1;
then A1:
( (incl S,T) .: X = X & ex_sup_of X,T & (incl S,T) . (sup X) = sup X )
by FUNCT_1:35, FUNCT_1:162, YELLOW_0:17;
then
"\/" X,T in the carrier of S
by YELLOW_0:def 19;
hence
"\/" ((incl S,T) .: X),T = (incl S,T) . ("\/" X,S)
by A1, YELLOW_0:65; :: thesis: verum