Explicit fusions

We introduce explicit fusions of names. An explicit fusion is a process that exists concurrently with the rest of the system and enables two names to be used interchangeably. Explicit fusions provide a small-step account of reaction in process calculi such as the pi calculus and the fusion calculus. In this respect they are similar to the explicit substitutions of Abadi, Cardelli and Curien, which do the same for the lambda calculus. In this paper, we give a technical foundation for explicit fusions. We present the pi-F calculus, a simple process calculus with explicit fusions, and define a strong bisimulation congruence. We study the embeddings of the fusion calculus and the pi calculus. The former is fully abstract with respect to bisimulation.