reserve T for non empty TopSpace;
reserve A for Subset of T;

theorem
  Int Cl Int KurExSet <> Cl KurExSet
proof
  set A = KurExSet;
  2 in [. 2,+infty .[ by XXREAL_1:236;
  then 2 in Cl A by Th10,XBOOLE_0:def 3;
  hence thesis by Th25,XXREAL_1:235;
end;
