Just a technical note: Mod 2 matrices are not the natural way to think about adjacency matrices (I learned this the hard way) - the entry is actually better thought of as the number of paths of length one from one vertex to another. That way taking nth powers of the matrices counts the number of n-paths from one vertex to another.
Let's not try to reduce NP-complete to polynomial in this thread... ;) Sorry, my point is an emphatic ++1 for including DLX in Sage. -- Robert M --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
