> On 4 July 2012 03:05, Maarten Derickx <m.derickx.stud...@gmail.com> wrote: >> Dear All, >> >> Today I was trying to compute some stuff using modular symbols. And I found >> the following slightly worrying:
Yup, this is definitely a bug. The "old submodule" it calculates isn't Hecke-invariant: sage: M.hecke_matrix(17).restrict(S.old_submodule().free_module()) [...] ArithmeticError: subspace is not invariant under matrix Note that S.old_submodule().hecke_matrix() will return something, but it'll be garbage, because it's restricting a matrix to a non-invariant submodule with checks disabled. Maarten, can you open a ticket for this? David -- 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
