Dear John, Wouldn’t be of some help to consider the kernel of f-Id (with Id the identity map)? Best, Pedro
El El jue, 25 ago 2022 a las 8:22, Dima Pasechnik <dimp...@gmail.com> escribió: > > > On Thu, 25 Aug 2022, 00:38 John H Palmieri, <jhpalmier...@gmail.com> > wrote: > >> I have a polynomial ring R = k[x1, x2, ..., xn] and a ring homomorphism >> f: R -> R. In case it matters, k=GF(2). I would like to find the subring of >> elements x satisfying f(x) = x: that is, I want to find the equalizer of >> the pair of maps (f, 1). Is there anything in Sage that will compute this? >> The more polynomial generators this can handle, the better. >> > > Is this subring finitely generated? Invariant theory in positive > characteristic is full of surprises... > > >> -- >> John >> >> -- >> 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/6b028ddf-d0b7-4156-adad-7315cc6220a1n%40googlegroups.com >> <https://groups.google.com/d/msgid/sage-support/6b028ddf-d0b7-4156-adad-7315cc6220a1n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- > 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/CAAWYfq3d%3DLMGOoXUyPhqRgzWfcMvrc%3DWZrxOTN7rfBg71VL06Q%40mail.gmail.com > <https://groups.google.com/d/msgid/sage-support/CAAWYfq3d%3DLMGOoXUyPhqRgzWfcMvrc%3DWZrxOTN7rfBg71VL06Q%40mail.gmail.com?utm_medium=email&utm_source=footer> > . > -- 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/CAOAJP6q3iZPq%2BdNtMOeSjNkm1R6cW-voXVKYtd6_2MhdjO7nCg%40mail.gmail.com.
