Abstract of Paper

Explicit Fusions
by Philippa Gardner and Lucian Wischik


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.