The Combinatorial Potlatch is a semi-regular (which for last 7 years has been yearly!) one-day workshop in combinatorics held in Cascadia.  It is very informal (no name tags!), very relaxed (only three talks!) and runs on next to no funding*.  The latest installment was this past weekend in Vancouver, BC, held at Simon Fraser University’s downtown campus.

I gave a version of my talk on constrained knapsack problems (joint work with Brent Heeringa and Gordon Wilfong).  It was a lot of fun!  The discrete math crowd was fun and patiently sat through my discussions of applications and algorithms and approximations until I finally got to the meat of the talk.  I don’t normally attend discrete math events, but this was a great way to meet people in the area who are graph-minded that I otherwise might not meet.  I also hope that all their best undergraduates will be pointed my way for grad school (hint hint hint).

Louis Deaett (University of Victoria) gave a talk on a (orthogonal) generalization of graph colouring to vector colours where one must assign linearly independent vectors to adjacent vertices while minimizing the dimension of the vectors.  This is certainly not something I had ever dreamt of before.  Only after having let the problem stew for a couple of days am I wondering if a notion can be (or already has been) used in the frequency assignment problem.  Rather than a node transmitting over one frequency, transmit over several; use independence to overcome interference.

Omer Angel (University of British Columbia) spoke on graphs that look the same everywhere from a local perspective.  Given a local pattern centred at a vertex, what kind of graph is such that every vertex has the same local pattern?  Can the graph be finite? Must it be infinite?  For example, if the local pattern is a degree-2 star, then the graph could be a cycle or an infinite path – there is no way of telling which it is.  Certainly, I thought, you could never tell if it is finite or infinite.  Not true.

So, thank you Nancy Ann Neudauer for inviting me, Luis Goddyn for arranging the superb location, and Rob Beezer for quickly correcting that I am a proud beaver, not a duck.

* The host institution provides a room and math-fuel (coffee).