On Tuesday, December 15, 2015 at 3:44:12 PM UTC-8, Nils Bruin wrote: > So something in sage's "sum" command causes maxima to store > a property on "n". It is possible we're triggering an error in maxima here: > Maxima does have a "scoping" system for assumptions that should > allow it to temporarily make assumptions for the benefit of local > simplfications and then later restore the original assumptions database > state. It could be that we're calling code in maxima that should use that > machinery but doesn't.
Yes, it appears that's exactly the case. Sage is interrupting the asksign request from Maxima, right? If I try that in a Maxima session I get: (%i20) sum(binomial(n-k,k), k, 0, n),simpsum; Is n positive or zero? Maxima encountered a Lisp error: Ctrl-C: User break Automatically continuing. To enable the Lisp debugger set *debugger-hook* to nil. (%i21) facts(); (%o21) [g24348 >= 0, n >= g24348] (%i22) is (n>=0); (%o22) true For the duration of 'sum', the index (the gensym here) is assumed to be between the lower and upper limits, inclusive. That implies the upper limit is >= the lower. Those assumptions aren't cleaned up when 'sum' is interrupted; that's a bug. If you can make a bug report about it, it would be helpful. It might have been reported already, I didn't look for it. best, Robert Dodier -- 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 https://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
