13 April 2018:

This week's progress:

1) Brandon Coya got a job interview at Whittier College! Cross your fingers and toes for Brandon.

2) Today Christian Williams is going to a Pyrofex developer's conference in Boulder, Colorado. After that he's gong to the RChain Spring Developer's Conference — for those of you not keeping score, Mike Stay's company Pyrofex is closely linked to Greg Meredith's company RChain, and both are interested in category theory. I'm hoping for a full report from Christian when he gets back - maybe even a blog article!

3) On Tuesday, Daniel Cicala gave a great talk in the network theory seminar on rewriting, going all the way from its origins in Chomsky's work on linguistics to graph rewriting, adhesive categories, and open objects in topoi! He covered a lot of ground in a very clear way.

4) Today Jade Master is speaking in the graduate student seminar about open Petri nets:


  • Jade Master, Open Petri nets and the reachability problem.



> In computer science Petri nets are diagrams which are used to represent the transfer of resources in complex interacting systems of agents. These systems don’t usually exist in isolation and instead have inputs and outputs corresponding to external or environmental factors. To model this interconnectedness we define open Petri nets; Petri nets which can be glued together along specified inputs and outputs. We form a category of open Petri nets with open Petri nets as morphisms between their sets of inputs and outputs. Computer scientists are often interested in which states of a Petri net are reachable from a given initial state. We will put the category of open Petri nets to use by constructing reachability as a lax functor from the category of open Petri nets to the category of relations.

5) I got myself invited to Oxford to visit Jamie Vicary from June 22nd to August 20th. Jamie has long been in Abramsky and Coecke's research group in computer science at Oxford. He's still working there part-time, but he's gotten a permanent position at the University of Birmingham - 67 miles away, but easy by train. So, I will be talking to Jamie and others about category theory and computer science.