Abstract of Paper |

*Explicit Fusions*

by Philippa Gardner and Lucian Wischik

**Abstract:**

We introduce {\em explicit fusions} of names. To `fuse' two names is to declare that they may be used interchangeably. An explicit fusion is one that can exist in parallel with some other process, allowing us to ask for instance ``how does this process behave in a context where $x=y$?''. We present the $\pi_F$-calculus---a simple process calculus with explicit fusions, similar in many respects to the fusion calculus but with a simple local reaction relation. We give embeddings of the $\pi$-calculus and the fusion calculus. We also give two bisimulation congruences for the $\pi_F$-calculus, with one contained in the other. The larger congruence is used to prove a full abstraction result for the embedding of the $\pi$-calculus. It is an open problem to determine whether the containment is strict---that is, whether contexts with explicit fusions are more discriminatory than substitutive contexts.