Re: polresultant disagrees with sage, maxima and magma

[Georgi Guninski <guninski@guninski.com>]

parisize = 8000000, primelimit = 500509
? q1=x2;q2=x2;polresultant(q1,q2,x1)
%1 = 0
? q1=x2;q2=x2;polresultant(q1,q2,x1)
%2 = 0
? p1=y;p2=y;polresultant(p1,p2,x1)
%3 = 1


On Thu, Sep 20, 2012 at 04:09:07PM +0300, Georgi Guninski wrote:
> I don't claim this is a bug in pari, more like a bug in the
> mentioned CAS.
> 
> ? p1=x2*(x3-x4);p2=x2*(x3-2*x4);polresultant(p1,p2,x1)
> %1 = 0
> 
> Since p1 and p2 certainly have common roots I expect the resultant
> w.r.t. x1 (not present in p1 or p2) to be able to vanish.
> 
> sage, maxima and magma return $1$ on the above testcase.
> 
> Can't see how it can be both ways, which is correct?