Salut, somehow, graphs don't like multiple edges very much:
sage: D = Graph() sage: D.allow_multiple_edges(True) sage: D.add_edges([(0,1),(0,1)]) sage: D.edges() [(0, 1, None), (0, 1, None)] sage: D.degree() [2, 2] sage: D.delete_edge(0,1) sage: D.edges() [(0, 1, None)] sage: D.degree() [2, 2] I looked into the code, but somewhere in the backend for graphs, I lost track of what the problem might be. For graphs without multiple edges, I didn't find this behaviour. I gonna open a ticket on this, if no one was already looking at it. Best, Christian -- 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