theorem
  p <> 0 implies denominator(p) = numerator(p)/p
proof
A1: (p"*p)*denominator(p)=p"*numerator(p);
  assume p<>0;
  then 1*denominator(p)=p"*numerator(p) by A1,XCMPLX_0:def 7;
  hence thesis;
end;
