Le mardi 18 novembre 2014 17:10:42 UTC+1, Chris Seberino a écrit : > > Emmanuel > > Any way to make Sage act like it can't find the solution (emit question > back to user) INSTEAD of emitting the empty set? > > "I can't find the solution" and "There is no solution" are NOT the same > thing? >
Indeed. But proving that "There is no solution" might inded invorve some serious work. Consider (pseudocode) : var("a,b,c,n") assume(a,"integer",b,"integer",c,"integer",n,"integer",a>0,b>0,c>0,n>2) solve(a^n+b^n==c^n,[a,b,c,n]) which has, indeed no solution. Proving this has been found a bit involved... So you can assume that an empty list means only that sage's algorithms find no solution. Your point is that, in your example, sage returns (incorrectly) an empty list.In other cases, it returns the original equation. Indeed. So what ? I have not (yet) found a specification for those two cases, but I think it depends on which algorithm has been used. (Maxima may return the empty list in cases solve'() does not succeds). Beware : in other cases, sage might return an implicit solution, given as an equation. > cs >>> >> -- You received this message because you are subscribed to the Google Groups "sage-support" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-support+unsubscr...@googlegroups.com. To post to this group, send email to sage-support@googlegroups.com. Visit this group at http://groups.google.com/group/sage-support. For more options, visit https://groups.google.com/d/optout.