Hi Jonas, On 2015-02-21, Jonas Jermann <jjerma...@gmail.com> wrote: > ZZ does not coerce into myElement.parent() so I end up in a much > larger space than myElement.parent(). However I would prefer if adding > zero didn't change the parent space.
If ZZ does not coerce into the parent of your element, then the parent is not a (unitary) ring. > One reason is for instance that > sum(...) no longer works properly because it always prepends "0+". You can avoid it by explicitly providing the starting element to the sum function. > Eg: from sage.modular.modform_hecketriangle.all import * > myElement = ModularForms().E4() > myElement.parent() != sum([myElement]).parent() > > Clearly "0" is a special case (the zero subspace does coerce into any of > the spaces). > > How should I fix this? By providing a starting point for the summation: sage: sum([myElement]).parent() ModularFormsRing(n=3) over Integer Ring sage: myElement.parent() ModularForms(n=3, k=4, ep=1) over Integer Ring sage: sum([myElement], myElement.parent().zero()).parent() ModularForms(n=3, k=4, ep=1) over Integer Ring Best regards, Simon -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
