If you try to test for equality in a finitely presented groupy the sage kernel can crash.
The following real life example leads to restarted kernel in the notebook interface and to "gap: cannot extend the workspace any more!" in Sage terminal interface (and nongraceful exit). k = 3 p = 18 d = 2*p/(p-6) l = 2*p*k/(p*k-2*k-2*p) F.<J,P,R1,R2>=FreeGroup() G = F / [J^3, P^(3*d), R1^p, R2^p, (F([-2,1]))^k, (F([4,3,1]))^l, F([-4,2,3,-2]), F([-4,1,3,-1]), F([-2,3,4])] k = G.rewriting_system() x = k.reduce(P^8) y = k.reduce(G([-4,2,3])) t = k.reduce(x*y) -- 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.