let L be complete LATTICE; :: thesis: for S being non empty full sups-inheriting SubRelStr of L holds S is complete LATTICE
let S be non empty full sups-inheriting SubRelStr of L; :: thesis: S is complete LATTICE
for X being Subset of S holds ex_sup_of X,S
proof end;
then S is complete by YELLOW_0:53;
hence S is complete LATTICE ; :: thesis: verum