Hi Sam, I don't use Sage Notebook, but both my own sage install and the cell server show "True" as the result. I suspect this is the right answer.
There have been updates to symmetric functions in the recent history of Sage, particularly #16560: http://trac.sagemath.org/ticket/16560 . If your Sage Notebook is older than 8 months, it might be a case of #15397 as well: http://trac.sagemath.org/ticket/15397 Best regards, Darij On Fri, Jul 18, 2014 at 8:53 PM, Sam Hopkins <samuelfhopk...@gmail.com> wrote: > Hi all, > > (First time posting to these forums) > > Sage is giving me inconsistent results about the Schur positivity of a > certain expression involving products of Schur functions. In the Sage Cloud, > I type: > > s = SymmetricFunctions(QQ).schur() > (s([8, 6, 5, 4, 3, 3, 1])*s([8, 7, 5, 3, 3, 2, 1]) - s([9, 6, 6, 5, 4, 3, > 1])*s([7, 7, 4, 2, 2, 2, 1])).is_schur_positive() > > and get output: "True" > > But in the Sage Notebook running on my own computer I type: > > s = SymmetricFunctions(QQ).schur() > (s([8, 6, 5, 4, 3, 3, 1])*s([8, 7, 5, 3, 3, 2, 1]) - s([9, 6, 6, 5, 4, 3, > 1])*s([7, 7, 4, 2, 2, 2, 1])).is_schur_positive() > > and get output: False > > I guess this could just be the result of the fact that this procedure is > memory intensive and the result on the Notebook is slower so I am inclined > to believe it is the one that is incorrect. Do you know which result I > should trust? The computation in question is very relevant to a conjecture > about general conditions for an expression of this form to be Schur > positive. > > Thanks a lot, > Sam Hopkins > > -- > You received this message because you are subscribed to the Google Groups > "sage-combinat-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-combinat-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-combinat-devel@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-combinat-devel. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-combinat-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-combinat-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-combinat-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-combinat-devel. For more options, visit https://groups.google.com/d/optout.
