Helsinki Univ. of Technology, Espoo (Finland), Research Report Series B, No. 2, January 1988.
Abstract: The report presents some open problems that have arisen in the context of using conflict-free labelled Petri Nets to model so-called self-timed or self-synchronizing circuits. The problems presented concern the concurrency of transitions in the marking class, formulation of a new concession rule for modelling mass phenomena, and modelling non-distributive Muller-diagrams by Petri Nets.