In modern society services and support provided by computer-based
systems have become ubiquitous and indeed have started to fund amentally
alter the way people conduct their business. Moreover, it has become
apparent that among the great variety of computer technologies available
to potential users a crucial role will be played by concurrent systems.
The reason is that many commonly occurring phenomena and computer
applications are highly con- current: typical examples include control
systems, computer networks, digital hardware, business computing, and
multimedia systems. Such systems are characterised by ever increasing
complexity, which results when large num- bers of concurrently active
components interact. This has been recognised and addressed within the
computing science community. In particular, sev- eral form al models of
concurrent systems have been proposed, studied, and applied in practice.
This book brings together two of the most widely used formalisms for de-
scribing and analysing concurrent systems: Petri nets and process
algebras. On the one hand, process algebras allow one to specify and
reason about the design of complex concurrent computing systems by means
of algebraic operators corresponding to common programming constructs.
Petri nets, on the other hand, provide a graphical representation of
such systems and an additional means of verifying their correctness
efficiently, as well as a way of expressing properties related to
causality and concurrency in system be- haviour.
