A Method for Describing Concurrent Problems Based on Logic

In this talk we investigate the usefulness of logic programming for the description of concurrent problems. A logic program consists of an axiomatization of the problem domain together with the specification of a certain control. To describe the axiomatization only a restricted form of predicate logic is used which is known as Horn clauses. For this class a “procedural interpretation” can be given. The control specification determines in which way procedure invocations should be executed. Synchronization of processes can be obtained with the help of a data structure the processes have in common.

Synchronization through data structures gives an implicit description of concurrent problems. To make it explicit we extend the concept of logic programming by introducing “message predicates”. Processes which are in the same message area can send or ask for messages. Sending a message does not affect the execution of a process while asking for a message delays a process until an appropriate message is received. The way in which information is passed between different processes through message predicates is the same as for the invocation of a procedure by a procedure call, i. e. unification. Therefore we have to demand that unification is an undivisible operation.

We give several examples for the capability of our method.

Authors and Affiliations

1. Institut für Informatik II, Universität Karlsruhe, Postfach 6380, D-7500, Karlsruhe 1, Fed. Rep. of Germany

   Georg Winterstein, Manfred Dausmann & Guido Persch

Editors and Affiliations

1. Fachbereich 10 - Angewandte Mathematik und Informatik, Universität des Saarlandes, 6600, Saarbrücken, Deutschland

   R. Wilhelm

Reprints and permissions

© 1980 Springer-Verlag Berlin · Heidelberg

Policies and ethics