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

theorem
  Int KurExSet <> Cl KurExSet
proof
  set A = KurExSet;
  5 in [. 2,+infty .[ by XXREAL_1:236;
  then
A1: 5 in Cl A by Th10,XBOOLE_0:def 3;
  Int A = ]. 4, 5 .[ \/ ]. 5,+infty .[ by Th18,TOPS_1:def 1;
  hence thesis by A1,XXREAL_1:205;
end;
