reserve x,y,z,X for set,
  T for Universe;

theorem Th6:
  for R being RelStr holds R is full SubRelStr of R
proof
  let R be RelStr;
  the InternalRel of R c= the InternalRel of R;
  then reconsider R9 = R as SubRelStr of R by YELLOW_0:def 13;
  the InternalRel of R9 = (the InternalRel of R)|_2 the carrier of R9 by
XBOOLE_1:28;
  hence thesis by YELLOW_0:def 14;
end;
