reserve x for set;
reserve a, b, c, d, e for Real;
reserve m, n, m1, m2 for Nat;
reserve k, l for Integer;
reserve p for Rational;

theorem Th24:
  a to_power 0 = 1
proof
  thus a to_power 0 = a #Z 0 by Def2
    .= 1 by PREPOWER:34;
end;
