Helloooo !!! > I'm ok with not being able to contract in a bipartite graph. I'm ok with being presented with an error. I'm NOT ok with my original graph suddenly being rubbish! (The net effect of merge_vertices is to delete vertex 4 in this case, which makes no sense).
You are right on this one. On the other hand, I am not ok either on not being able to contract an edge in a graph produced by Sage, unless I have decided myself that the graph should *stay* bipartite, which clearly isn't the case in this example of code. Ryan, what would you think of deciding that Sage's constructors only return Graph objects to prevent such problems ? Besides fixing this problem which should easily be done :-) Nathann -- 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
