
theorem Th13:
  for a be Element of F_Complex holds a*a*' = |.a.|^2
proof
  let z be Element of F_Complex;
  reconsider a = z as Element of COMPLEX by COMPLFLD:def 1;
  thus z*z*' = |.a.|^2+0*<i> by Th4
    .= |.z.|^2;
end;
