reserve x, X, Y for set;

theorem
  for L being RelStr for S, T being full SubRelStr of L st the carrier
  of S c= the carrier of T holds the InternalRel of S c= the InternalRel of T
proof
  let L be RelStr, S1,S2 be full SubRelStr of L;
  the InternalRel of S1 = (the InternalRel of L)|_2 the carrier of S1 &
the InternalRel of S2 = (the InternalRel of L)|_2 the carrier of S2 by
YELLOW_0:def 14;
  hence thesis by Th5;
end;
