On Fri, May 30, 2014 at 9:14 AM, John Cremona <john.crem...@gmail.com> wrote: > On 30 May 2014 15:57, Peter Mueller <ypf...@googlemail.com> wrote: >> The lines >> >> sage: k.<n> = FunctionField(QQ) >> sage: R.<X> = k[] >> sage: l.<x> = k.extension(X^3+n-1) >> sage: E = EllipticCurve(l,[0,n]) >> sage: print 1 == x^3+n >> True >> >> show that the point (x,1) lies on the elliptic curve E, which is defined >> over l too. >> However, E(x,1) fails with an intimidating traceback, with the last line >> being >> >> AttributeError: 'FunctionField_polymod_with_category' object has no >> attribute 'parent' >> >> Am I doing something wrong, or is there a bug in a very basic function? > > You are not doing anything wrong, but I would call it more of a > NotImplementedError than a bug. We don't have good support for > function fields yet, or for elliptic curves over function fields. But > still, that error message is bad. >
My recollection is that the sum total of work on function fields in Sage was a few days that Robert Bradshaw and I spent coding up some extremely basic functionality, probably about 5 years ago. That's it. Don't expect much. I've hired Andrew Ohana to rewrite function fields this summer, and add more interesting functionality (e.g., implement Hess's algorithm). Let's encourage him. -- William > > John Cremona > >> >> -- Peter Mueller >> >> >> -- >> 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 post to this group, send email to sage-support@googlegroups.com. >> Visit this group at http://groups.google.com/group/sage-support. >> For more options, visit https://groups.google.com/d/optout. > > -- > 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 post to this group, send email to sage-support@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-support. > For more options, visit https://groups.google.com/d/optout. -- William Stein Professor of Mathematics University of Washington http://wstein.org -- 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 post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.
