reserve E for non empty set;
reserve a for Element of E;
reserve A, B for Subset of E;
reserve Y for set;
reserve p for FinSequence;
reserve e, e1, e2 for Singleton of E;

theorem
  for E being finite non empty set holds prob([#] E, [#] E) = 1
proof
  let E be finite non empty set;
  prob([#] E) = 1 by XCMPLX_1:60;
  hence thesis;
end;
