Despite my earlier comment I am not proposing automatic coercion between isomorphic number fields since there is (often, not always!) more than one isomorphism.
Surely a number field + embedding is a richer structure than an abstract number field, so the coercion should go from the former to the latter as a forgetful functor. Are you going to similarly come up with the question of coercion between two number fields which are the same abstract field and with mathematically the same embedding, but with one of higher precision than the other? John PS What's wrong with sage-nt?! On Thu, Nov 25, 2010 at 7:38 AM, Simon King <simon.k...@uni-jena.de> wrote: > On 24 Nov., 23:56, Simon King <simon.k...@uni-jena.de> wrote: >> > I never use these canonical embeddings, and cannot think of a reason >> > for defining one field twice in this way... >> >> Well, it is imaginable that some automatic constructions (say, in >> pushout) create such a situation. And if it occurs, the program should >> know how it is supposed to cope with it. > > The reason for my question was a bug that I introduced while working > at #8800. I can solve it by being more careful with the data stored in > the construction functors, and also by allowing broader conversion > (not coercion) between different number fields. > > Nevertheless, I think this case of coercion between a number field > with and a number field without embedding (which direction??) should > be covered. > > Cheers, > Simon > > -- > To post to this group, send an email to sage-devel@googlegroups.com > To unsubscribe from this group, send an email to > sage-devel+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
