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

theorem
  Cl Int KurExSet <> Int KurExSet
proof
  set A = KurExSet;
  4 in Cl Int A & Int A = ]. 4, 5 .[ \/ ]. 5,+infty .[ by Th18,Th24,
TOPS_1:def 1,XXREAL_1:236;
  hence thesis by XXREAL_1:223;
end;
