Am Mittwoch, 11. März 2020 03:43:18 UTC+1 schrieb Nils Bruin:
>
> I think the general way (which should be pretty performant for such a nice
> example) is to do it via reduction wrt. the graph ideal:
>
> sage: R.=PolynomialRing(QQ,order="degrevlex(2),degrevlex(3)")
> sage:
On Tuesday, March 10, 2020 at 6:22:45 AM UTC-7, Dima Pasechnik wrote:
>
> Suppose I have
>
> R.=QQ[]
> K.=QQ[]
> f=R.hom([u*v,u^2,v^2-u^2])
>
> then for any even degree p in K one can compute
> a preimage under f (e.g. u^4-u*v goes to y^2+x, etc)
>
I think the general way (which should be
