Re: polresultant disagrees with sage, maxima and magma

[Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>]

* Bill Allombert [2012-09-20 17:57]:
> On Thu, Sep 20, 2012 at 05:05:25PM +0200, Karim Belabas wrote:
> > It should have worked, and this was a bug in PARI. All such examples should be
> > fixed in master HEAD after the following commit:
> > 
> >   commit 7079c4f7813c582949dea92a3089bf6a6c532738
> >   Author: Karim Belabas <Karim.Belabas@math.u-bordeaux1.fr>
> >   Date:   Thu Sep 20 16:23:33 2012 +0200
> > 
> >       fix: resultant(x,x,y) -> 0 and related problems
> > 
> >       Original bug report:
> >         p1=x2*(x3-x4);p2=x2*(x3-2*x4);polresultant(p1,p2,x1) -> 0. Should be 1
> 
> Should I backport it to pari 2.5.3 ?

Fine with me. It should be stable enough. :-)

We have a pending proposed patch by Jeroen to introduce new variables of
arbitrary priorities (not limited by 0 or MAXVARN) which would simplify
and make such constructs more robust [ scheduled for 'testing' in the
near future ]. But the current fix is good enough for stable.

Thanks !

    K.B.
-- 
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite Bordeaux 1          Fax: (+33) (0)5 40 00 69 50
351, cours de la Liberation    http://www.math.u-bordeaux1.fr/~belabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux1.fr/  [PARI/GP]
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