On the Expressiveness of Joining and Splitting

Abstract

An ongoing theme of the work of Bernhard Steffen has been the bringing together of different components in a coordinated manner and with a unified language. This paper explores this approach applied to process calculi that account for coordination of different kinds of workflows. Coordination here extends binary interaction to also account for joining of multiple outputs into a single input, and splitting from a single output to multiple inputs. The results here formalise which process calculi can and cannot be encoded into one another, and thus which language has the required expressiveness for given workflow properties. The combination of with other features of interaction allows for the representation of many systems and workflows in an appropriate calculus.