reserve E, x, y, X for set;
reserve A, B, C for Subset of E^omega;
reserve a, b for Element of E^omega;
reserve i, k, l, kl, m, n, mn for Nat;

theorem
  m <= n implies (A |^ m)* c= (A |^ (m, n))* by Th20,FLANG_1:61;
