reserve E, x, y, X for set;
reserve A, B, C, D for Subset of E^omega;
reserve a, a1, a2, b, c, c1, c2, d, ab, bc for Element of E^omega;
reserve e for Element of E;
reserve i, j, k, l, n, n1, n2, m for Nat;

theorem
  A* = (A \ {<%>E})*
proof
  thus (A \ {<%>E})* = ((A \ {<%>E}) \/ {<%>E})* by Th48,Th68
    .= (A \/ {<%>E})* by XBOOLE_1:39
    .= A* by Th48,Th68;
end;
