let R be Relation; :: thesis: for S being integer-valued Relation st R c= S holds
R is integer-valued
let S be integer-valued Relation; :: thesis: ( R c= S implies R is integer-valued )
assume R c= S ; :: thesis: R is integer-valued
then A1: rng R c= rng S by RELAT_1:11;
rng S c= INT by Def3i;
hence rng R c= INT by A1; :: according to VALUED_0:def 5 :: thesis: verum