2021-04-28 15:32 UTC+2, Ilia: > On Saturday, April 24, 2021 at 1:33:36 AM UTC+2 slelievre wrote: > > Could this have to do with one of the following existing tickets? > > > > - Sage Trac ticket 22008 > > complex_embedding on relative number fields is inconsistent with the base > > field > > https://trac.sagemath.org/ticket/22008 > > This is indeed related: it also involves Sage mistaking the extension [L:K] > for the extension [L:QQ]. But it does not seem to be the exact same > problem: I am not sure that fixing ticket 17524 would automatically > fix the problem I am describing here. Well, it *might*; but the only way > to be sure is to actually pinpoint the problem - and this would involve > a complex hunt through a lot of different code files that I (being a total > newbie to Sage development) do not feel like doing right now. > > > - Sage Trac ticket 17524 > > polynomial for relative number field elements > > https://trac.sagemath.org/ticket/17524 > > This one, OTOH, seems a bit different: in this one, there is no confusion > between [L:K] and [L:QQ], but simply a problem of consistency between > the chosen embedding of K when taken by itself and the chosen > embedding of K when seen as a subfield of L.
I agree. > On Saturday, April 24, 2021 at 9:51:27 PM UTC+2 vdelecroix wrote: >> >> At least on 9.3.rc4 it is fixed by using instead >> >> sage: K.<sqrt2> = QuadraticField(2, embedding=AA(2).sqrt()) >> sage: L.<s> = K.extension(x^3 + (sqrt2/2 + 1/3)*x^2 + (2*sqrt2/5+3/7)*x - 1) >> sage: phi0 = hom(L, QQbar, roots[0]) >> sage: phi1 = hom(L, QQbar, roots[1]) >> sage: phi2 = hom(L, QQbar, roots[2]) >> sage: phi0(sqrt2) >> 1.414213562373095? >> sage: phi1(sqrt2) >> 1.414213562373095? + 0.?e-17*I >> sage: phi2(sqrt2) >> 1.414213562373095? + 0.?e-17*I > > > For what it is worth, in my config (version 9.1), this gives > a "ValueError: relations do not all (canonically) map to 0 > under map determined by images of generators". So, OK, > presumably this has been fixed in the meanwhile. You can try Sage 9.2 at SageCell: https://sagecell.sagemath.org > But anyway, > where can I find documentation for the "hom" method? sage: hom? sage: hom?? sage: browse_sage_doc(hom) sage: Hom? sage: Hom?? sage: browse_sage_doc(Hom) https://doc.sagemath.org/html/en/reference/categories/sage/categories/homset.html https://doc.sagemath.org/html/en/reference/categories/sage/categories/homsets.html > Assuming it works, OK, thank you, it is a good workaround. > Still, in the meanwhile, I think that something needs to be > done about NumberFieldEmbedding: it should either be > fixed, be deprecated, or at least the documentation should > be updated to signal that it does not work in relative fields. > So I guess I will now try to open a ticket. Sounds good. --Samuel -- 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/CAEcArF3EvkUJcoKOAkGaSD5ZRvVARc7_vFAW%2BxgDsGZkh0UWtQ%40mail.gmail.com.
