Tomorrow, Martin will give a seminar at Queen Mary University of London on a recent collaboration with Peter Mosses and Mohammad Reza Mousavi on extending the notion of well-supported proof (for transition systems with negative premises) to open rules. The paper is Modular Semantics for Transition System Specifications with Negative Premises, and it will appear at the CONCUR conference later this year.
Update: slides now available. tonga . web page alert