Bill Allombert on Sun, 04 Aug 2013 15:09:15 +0200

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Re: Why are some minus signs not cancelled?

On Sun, Aug 04, 2013 at 07:20:17AM +0200, Dirk Laurie wrote:
> Why does Pari/GP simplify -1/-2 to 1/2 but not -1/-x to 1/x?

1/2 is a t_FRAC which has a normal form.

-1/-x is a t_RFRAC which does not have a normal form in general, or at
least this is expensive to compute, so PARI does not attempt to do it.