I said last time that I was interested in finding colourings for graphs that have lots of fully connected subgraphs, aka "cliques". For instance, I'd like to find a four-colouring for this sixteen-node graph: Yuck. What a mess. What this graph...

Let's give it a try. Can we colour South America with only four colours? Let's start by stating what all the edges are in the graph of South America: const int Brazil = 0; const int FrenchGuiana = 1; const int Suriname = 2; const int Guyana = 3;...

OK, we've got our basic data structures in place. Graph colouring is a very well-studied problem. It's known to be NP-complete for arbitrary graphs, so (assuming that P!=NP) we're not going to find an always-fast algorithm for colouring an arbitrary...

Before I begin a quick note: congratulations and best wishes to David Johnson, currently the president of my alma mater, the University of Waterloo. The Queen has appointed him to be the next Governor General of Canada come this October. For those of...

As regular readers know, I'm interested in learning how to change my C# programming style to emphasize more concepts from functional programming, like use of immutable rather than mutable data structures and use of declarative control flow like LINQ queries...

The remaining video of the talk with Neal Gafter and me at NDC is up on the streaming content server now, here . However, spoiler alert: if you don't want to know the solutions to the eight puzzles we present, don't watch the video. Of course, long...

No computers today, but some interesting - and important - math. (And, happy Canada Day, Canadians!) " Car Talk " is a popular weekly phone-in program that has been on National Public Radio for several decades now, in which Bostonian brothers Tom and...