Hi, I am trying to do some calculations with decomposition factors of modular symbol spaces, for some of which I intend to use the projection function. My problem is that most of the time, when I try to define a projection map onto a modular symbol subspace, I get an error.
Sometimes the error specifies that the projection function is only implemented for decomposition factors, but sometimes I am trying to define it for a decomposition factor and I get a different error. Example: S=Newforms(23,2,names='a') K=S[0].hecke_eigenvalue_field() M=ModularSymbols(23,2,base_ring=K) N=M.cuspidal_submodule().minus_submodule().decomposition() P=N[0].projection() This gives back an error: ValueError: list.index(x): x not in list It only seems to happen because I used minus_submodule() in the fourth line. If I don't do that, it no longer gives an error, but it's now projecting to a bigger space than the one I want. Am I making some kind of syntax error that's causing this to happen? Or does the projection function just not work for this kind of subspace? -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
