Institute for Informatics
Georg-August-Universität Göttingen

Databases and Information Systems

Uni Göttingen

7th International Joint Conference on the Theory and Practice of Software Development (TAPSOFT'97),
Lille, France, April 14-18, 1997. LNCS 1214, Springer, pp. 535-549.

Specifying Complex and Structured Systems with Evolving Algebras

Wolfgang May


This paper presents an approach for specifying complex, structured systems with Evolving Algebras by means of aggregation and composition. Evolving algebras provide a formal method for executable specifications which has been employed for specifying several algorithms and programming languages. With its transition system-like rule-based syntax, the concept is as well very intuitive as well-suited for formal reasoning and verification.

Following the need for structuring capabilities in specification frameworks, the paper proposes a concept for hierarchically structuring Evolving Algebras corresponding to the semantics of the system to be modeled, allowing to build up complex systems from simpler ones by several combinators. The concept can be generalized to arbitrary rule-based state-oriented formalisms.

In such systems, transitions regarded as atomic on the corresponding level are allowed to be specified by computations performed by sub-Evolving-Algebras instead of single rules. The subsystems provide a natural way of encapsulating data and behaviour while a computation is running. Communication is done via distinguished locations accessible to the participating systems.


The paper is based on

  • [Slides] given at "Workshop on Evolving Algebras", May 17-19, 1996, Schloß Eringerfeld, Germany
  • [Report]