Racks and Tangled Circuits

This is just a link  (https://dl.dropboxusercontent.com/u/92056191/walters-aurelio-talk-24062013.pdf) to the slides of the lecture I gave at the conference this week in Milan in memory of Aurelio Carboni.  The lecture starts with some memories of working with Aurelio (I said more at the conference!) putting some recent work in context.

I noticed while writing the slides that I had not separated the properties of racks sufficiently from those of the new notion of irack - I will probably write up a clearer version for arxiv.

Update: The promised arxiv paper is at http://arxiv.org/abs/1307.5404.