reserve U for Universe;
reserve x for Element of U;
reserve U1,U2 for Universe;

theorem Th61:
  for o,m being object holds 1Cat(o,m) is U-petit
  proof
    let o,m be object;
    reconsider o2 = {},m2 = {} as Element of U by CLASSES2:56;
    1Cat(o2,m2) is U-element by Th55;
    hence thesis by Th60;
  end;
