And if you accept to sligthly change the graph, you can add a universal vertex v to it. If u is of color red, color edge uv with red, and the same for all vertices. Do this in both graph and all will be fine :-)
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
