John, At the end of the spring I began working on porting your Magma code implementing Tate's algorithm for elliptic curves and p-adic heights to Sage. I made a lot of progress, but discovered that I needed to write a few new classes for elliptic curves over number fields. It sounds like some of the infrastructure that you're trying to implement is exactly what I was working on before I got too busy this summer to work on Sage.
I have some time to work on Sage this week. Let me know when you're free and perhaps you, David and I can work on it together, though this might be interesting given our different time zones (I'm in Boston). another David On 9/24/07, John Cremona <[EMAIL PROTECTED]> wrote: > > > David, > > I'm sure you are right but doing that on my own (and in the next day > or two) is beyond my sage/python capabilities... to start with (and > as these isomorphisms of Weierstrass models are so much simpler than > more general isogenies) I was going to be much more simple-minded and > just have a list [u,r,s,t] of elements on the field of definition of > the curve, with no fancy parent structure. > > On the other hand, if you'll have some time this week then perhaps we > could do it as a joint effort from which I would learn a lot! > > John > > On 9/24/07, David Kohel <[EMAIL PROTECTED]> wrote: > > > > Hi John, > > > > I would strongly suggest that this construction be compatible > > with isogenies (also yet to be implemented). Thus one should > > be able to compose isomorphisms and isogenies with one > > another. Moreover, one should be able to access the defining > > polynomials -- this is useful to verify the definitions of > > coefficients > > of the transformations u,r,s, and t. > > > > The intend is that isomorphisms would have a parent structure > > Iso(E,F) [or Isom(E,F)] and Aut(E) = Iso(E,F) which really only > > need to coerce into the more general Hom(E,F) and End(E). > > > > Certainly the transformations would be useful for construction > > of minimal models. > > > > If a proper class of isogenies is defined, then adding the parent > > and coercions can be added easily. > > > > --David > > > > > > > > > > > > -- > John Cremona > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
