One of the positive things that happened during my sabbatical from posting on this diary was that I helped contribute to the writing of the paper On the Axiomatizability of Priority that I co-authored with Taolue Chen, Wan Fokkink and Anna Ingólfsdóttir. (As a consequence of this joint paper, my Taolue Chen number is now 1.) An extended abstract of that paper will appear in the proceedings of ICALP 2006.
The aforementioned paper studies the equational theory of bisimulation equivalence over the process algebra BCCSP extended with the classic priority operator theta of Baeten, Bergstra and Klop. Those who know my partiality for negative results won't be overly suprised to read that the main results in that paper are non-finite axiomatizability results that add the priority operator to the "bestiary" of operations from process theory that spoil the finite axiomatizability result for bisimilarity over BCCSP.
Are these results "interesting"? Well, they certainly won't change anybody's life, but I like them, despite the amount of effort that it takes to achieve them. I hope that a couple of readers will find them worth reading too.
Not all of my recent output is devoted to negative results though. I was lucky enough to contribute to the development of another paper during the last few months, but that will be the subject of another post.
[In case you wonder whether those papers would have been written without my collaborators, the answer is a resounding "No!"]