
theorem Th12:
  for a be Element of F_Complex st Im a = 0 holds a = a*'
proof
  let x be Element of F_Complex;
  reconsider d = x as Element of COMPLEX by COMPLFLD:def 1;
  assume Im x = 0;
  hence x = Re d+(-Im d)*<i> by COMPLEX1:13
    .= x*';
end;
