Let's rewrite: * abelian groups * permutations groups * piecewise functions * Sage's riemann_roch_basis command (wrapping Brill-Noether)...
William On Thu, May 20, 2010 at 12:58 PM, Dima Pasechnik <dimp...@gmail.com> wrote: > Indeed, somehow people who wrote the permutation groups code in Sage > kept forgetting that > a permutation group is a pair (G,X), where G is a group and X is a > set, on which G acts. > Once you think that you can get away with permutations alone, you are > doomed... > (same would apply to any group actions, not only to permutation ones; > e.g. if you have a linear group, don't even try to forget which > vectorspace it operates on) > > Sorry for sounding like a grumpy algebra professor :-) > Dima > > > On May 20, 3:22 am, Dan Christensen <j...@uwo.ca> wrote: >> Most of this discussion is about cases where sage thinks it is acting on >> a bigger set than the user wants it to. I'll just point out bug 8963 >> >> http://trac.sagemath.org/sage_trac/ticket/8963 >> >> where sage has the reverse problem: it thinks that the set that is >> being acted on is smaller. For example, it correctly computes that >> the row stabilizer group of the tableau [[1,2],[3]] is a group with >> two elements generated by the transposition (1,2), but it thinks that >> this group is acting on the set {1, 2} rather than the set {1, 2, 3}, >> and this leads to difficulties. >> >> That bug has a patch that fixes this particular problem, but enhancing >> sage to know about the set that a permutation group acts on sounds like >> a good idea. >> >> Dan >> >> -- >> 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 >> athttp://groups.google.com/group/sage-devel >> URL:http://www.sagemath.org > > -- > 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 > -- William Stein Professor of Mathematics University of Washington http://wstein.org -- 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
