The legacy of Carl Adam Petri: From automata to communication

This paper takes a look at the conceptual foundations of Petri's net theory, including the crucial contribution by Anatol Holt to its development. We focus on several aspects which, although neglected in the mainstream of the literature on Petri nets, still bear, in our opinion, a value, both theoretically and in applications. Specifically, we deal with the notion of "formal pragmatics", and with the role of computers as a medium for organized communication, which should, in Petri's view, be paired with a general theory of information flow. A section will be devoted to the relations between Petri's theory and the formal apparatus of physics, a topic to which Petri gave special importance.