reserve T for TopSpace,
  A, B for Subset of T;

theorem Th2:
  Cl Int Cl (A \/ B) = Cl Int Cl A \/ Cl Int Cl B
proof
  set C = Cl A, D = Cl B;
  Cl Int C \/ Cl Int D = Cl Int(C \/ D) by TDLAT_1:6;
  hence thesis by PRE_TOPC:20;
end;
