Thanks, I was just being stupid. John
On Apr 27, 9:19 pm, William Stein <[email protected]> wrote: > On Tue, Apr 27, 2010 at 12:04 PM, John Cremona <[email protected]> wrote: > > Thanks for *not* complaining about the "multiplicative" in "Torsion > > Subgroup isomorphic to Multiplicative Abelian Group..." > > > I once wrote a patch to fix that but no-one liked it enough. > > > I also tried E.change_ring(QQbar).torsion_subgroup() but that failed > > for a different reason! For some reason, E.change_ring(Qbar) has this > > type: > > > sage: type(E.change_ring(QQbar)) > > <class > > 'sage.schemes.elliptic_curves.ell_generic.EllipticCurve_generic'> > > > while > > > sage: type(EllipticCurve(QQbar, E.a_invariants())) > > <class 'sage.schemes.elliptic_curves.ell_field.EllipticCurve_field'> > > > which is inconsistent; and neither helps, since EllipticCurve_field > > objects don't have a torsion subgroup.... > > > Some of this should be easy to fix. Assuming that you could do > > something useful with the torsion subgroup over QQbar! > > > Wait a minute: in what sense is the torsion subgroup of J_0(11) of > > structure [5,5] anyway? Over Q it is cyclic of order 5, while over > > QQbar it is (Q/Z)^2 . So the output is worse than you thought! > He wrote: > > sage: A.torsion_subgroup(5) > Finite subgroup with invariants [5, 5] over QQ of Abelian variety > J0(11) of dimension 1 > > In general, A.torsion_subgroup(n), gives "the n-torsion subgroup". > > william > > -- > To post to this group, send email to [email protected] > To unsubscribe from this group, send email to > [email protected] > For more options, visit this group > athttp://groups.google.com/group/sage-support > URL:http://www.sagemath.org -- To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
