The motivation for, and certain terminology in, this paper depend on a previous paper by the second author [1], in which he introduced coordinated table selective substitution, or cts systems, which supposedly provide a unifying framework for various types of automata and grammars. A cts system is a kind of product of “sequential” grammars.

The main result of the present paper is that there is a certain subclass of cts systems that is equal to the class of labeled marked Petri nets. The authors state in the Introduction that they will “indicate how this relationship can be exploited to the advantage of both theories.” However, in the reviewer’s opinion, there is little evidence in this paper of how the theory of Petri nets benefits from this relationship.