reserve i, x, I for set,
  A, B, M for ManySortedSet of I,
  f, f1 for Function;
reserve SF, SG for SubsetFamily of M;
reserve E, T for Element of Bool M;
reserve g, h for SetOp of M;

theorem :: CLOSURE:21
  g is reflexive & h is reflexive implies g * h is reflexive
proof
  assume
A1: g is reflexive & h is reflexive;
  let X be Element of Bool M;
  X c= h.X & h.X c= g.(h.X) by A1;
  then dom h = Bool M & X c= g.(h.X) by FUNCT_2:def 1,PBOOLE:13;
  hence thesis by FUNCT_1:13;
end;
