The future of journals II

If you have scrutinized the list of signatories of the boycott of Elsevier you may have noticed the absence of my name. I admit to being cautious.

Read more »

The future of journals

I have been watching the reaction to Timothy Gower's blog post about the future of mathematical journals, and the stranglehold a small number of commercial publishers have over the printed results of mathematical research.

It occurs to me that one obvious response is to ask for payment for work done for commercial publishers.

Read more »

Petri nets and Span(Graph) II

I mentioned in the last post the close relation between Petri nets and multigraphs. (I  will ignore the difference between them in these remarks.) Of course I was speaking only of the net structure, not the states and dynamics (though a suggested categorical dynamics of a Petri net/multigraph may be obtained by considering the free symetric monoidal category on the multigraph - Meseguer, Montanari).
Read more »

Petri nets and multigraphs

This post is to explain a connection in this earlier post.

Graphs are an extremely useful tool in designing and planning, and there are a host of different types. Computer scientists often think of a graph as a binary relation from a set X to X. Another type well-known to category theorists is the following: a graph consists of two sets Arcs and Vertices and two functions, source and target : Arcs -> Vertices.
Read more »