Ah, that explains it! I tried b = FormalSum([(2,'x')],parent=GF(7))
when I should have tried b = FormalSum([(2,'x')],parent=FormalSums(GF(7))) The latter gives me sage: 5*b 3*x sage: 5*b == 12*b True and this is what I wanted. Thanks a lot, Christian John Cremona wrote: > Your mistake is to force the parent to be GF(7). The parent is not > the coefficient ring. Try > sage: FormalSum? > Type: type > Base Class: <type 'type'> > String Form: <class 'sage.structure.formal_sum.FormalSum'> > Namespace: Interactive > File: /home/john/sage-3.4.2/local/lib/python2.5/site-packages/sage/ > structure/formal_sum.py > > Constructor information: > Definition: FormalSum(self, x, parent=Abelian Group of all Formal > Finite Sums over Integer Ring, check=True, reduce=True) > > What were you trying to do? > > John Cremona > > On May 9, 1:00 pm, Christian Nassau <nas...@nullhomotopie.de> wrote: >> Hi, >> >> FormalSum arithemtic appears to be broken when the parent is a Galois field: >> >> sage: a = FormalSum([(1,'x')],parent=GF(7)) >> sage: 1*a >> 0 >> sage: a*1 >> --------------------------------------------------------------------------- >> TypeError Traceback (most recent call last) >> >> /home/cn/sg2/sage-3.4-linux-openSUSE_11.1_x86_64-x86_64-Linux/<ipython >> console> in <module>() >> >> /home/cn/sg2/sage-3.4-linux-openSUSE_11.1_x86_64-x86_64-Linux/local/lib/python2.5/site-packages/sage/structure/element.so >> in sage.structure.element.ModuleElement.__mul__ >> (sage/structure/element.c:6599)() >> >> /home/cn/sg2/sage-3.4-linux-openSUSE_11.1_x86_64-x86_64-Linux/local/lib/python2.5/site-packages/sage/structure/coerce.so >> in sage.structure.coerce.CoercionModel_cache_maps.bin_op >> (sage/structure/coerce.c:5848)() >> >> TypeError: unsupported operand parent(s) for '*': 'Finite Field of size >> 7' and 'IntegerRing' >> >> This is with Sage version 'Sage Version 3.4, Release Date: 2009-03-11'. >> Is there a tracker where I should report this as a bug? >> >> Christian > > > --~--~---------~--~----~------------~-------~--~----~ 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 URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
