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

theorem Th25:
  Int Cl Int KurExSet = ]. 4,+infty .[
proof
  set A = KurExSet;
  Cl Int A = Cl (Cl A`)` by TOPS_1:def 1;
  then
A1: Int Cl Int A = (Cl (Cl (Cl A`)`)`)` by TOPS_1:def 1;
  (Cl (Cl A`)`)` = ]. -infty, 4 .[ by Th19,TOPMETR:17,XXREAL_1:224,294;
  then Cl (Cl (Cl A`)`)` = ]. -infty, 4 .] by BORSUK_5:51;
  hence thesis by A1,TOPMETR:17,XXREAL_1:224,288;
end;
