|Bill Allombert on Thu, 20 Sep 2012 17:57:05 +0200|
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|Re: polresultant disagrees with sage, maxima and magma|
On Thu, Sep 20, 2012 at 03:19:52PM +0100, John Cremona wrote: > > I don't think this is a good enough answer (sorry, Bill!). I know > that there are reasons for pari's variable priorities, and I have > personally been entertained by hem for many years, but if > "polresultant(p1,p2,x1)" is to correspond to any mathematically > correct resultant function then it has to be independent of that > (invisible) priority. I agree with you, I was just pointing out the discrepancy! 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 ? Cheers, Bill.