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.<u,v,x,y,z>=PolynomialRing(QQ,order="degrevlex(2),degrevlex(3)") > sage: I=R.ideal([x-u^2,y-u*v,z-v^2]) > sage: inv=lambda f:QQ['x,y,z']((I.reduce(f))) > sage: inv(u^2) > x > > Obviously, the term order chosen will dictate what representative you get > back, if the map isn't injective. You should of course choose an > elimination order. >
I think it would be nice if we implemented this. It might not solve the very complicated cases, but most of the time when I want an inverse I already know that it can be computed easily, such as for linear or triangular transformations. Doing this computation manually every time is a bit cumbersome. -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-support/d784633b-a59c-4583-82c8-7f16afb37ac6%40googlegroups.com.
