theorem Th21:
  a |^ 0 = 1_GF(p) & a |^ 0 = 1
  proof
    thus A1: a |^ 0 = 1_GF(p) by BINOM:8;
    p > 1 by INT_2:def 4;
    hence a |^ 0 = 1 by A1,INT_3:14;
  end;
