The main idea behind the series of volumes Advances in Petri Nets is to present to the general computer science community recent results which are the most representative and significant for the development of the area. The papers for the volumes are drawn mainly from the annual International Conferences on Applications and Theory of Petri Nets. Selected papers from the latest conference are independently refereed, and revised and extended as necessary. Some further papers submitted directly to the editor are included. Advances in Petri Nets 1990 covers the Tenth International Conference on Applications and Theory of Petri Nets held in Bonn, Germany, in June 1989. Additional highlights of this volume include a tutorial on refinements of Petri nets by W. Brauer, R. Gold, and W. Vogler, and a tutorial on analysis and synthesis of free choice systems by J. Esparza and M. Silva, both prepared in the framework of the ESPRIT Basic Research Actions Project DEMON.

A survey of behaviour and equivalence preserving refinements of petri nets.- A distributed simulator for high order Petri nets.- Petri nets with uncertain markings.- Convex geometry and semiflows in P/T nets. A comparative study of algorithms for computation of minimal p-semiflows.- Improving the linearly based characterization of P/T nets.- Linear invariants in commutative high level nets.- Vicinity respecting net morphisms.- Regular stochastic petri nets.- Circuits, handles, bridges and nets.- On the analysis and synthesis of free choice systems.- Petri net models of a distributed election protocol on a unidirectional ring.- Hierarchies in coloured petri nets.- Coloured petri nets: A high level language for system design and analysis.- A simulation system architecture for graph models.- A state transformation preorder over a class of EN systems.- Composition of nets via a communication medium.- ?Trellis: A system for writing and browsing petri-net-based hypertext.- Stubborn sets for reduced state space generation.