Abstract
The pi-calculus with synchronous output and mixed-guarded choices is strictly more expressive than the pi-calculus with asynchronous output and no choice. This result was recently proved by C. Palamidessi and, as a corollary, she showed that there is no fully compositional encoding from the former into the latter that preserves divergence-freedom and symmetries. This paper argues that there are nevertheless "good" encodings between these calculi. In detail, we present a series of encodings for languages with (1) input-guarded choice, (2) both input and output-guarded choice, and (3) mixed-guarded choice, and investigate them with respect to compositionality and divergence-freedom. The first and second encoding satisfy all of the above criteria, but various "good" candidates for the third encoding-inspired by an existing distributed implementation-invalidate one or the other criterion, While essentially confirming Palamidessi's result, our study suggests that the combination of strong compositionality and divergence-freedom is too strong for more practical purposes. (C) 2000 Academic Press.
| Original language | English |
|---|---|
| Journal | Information and Computation |
| Volume | 156 |
| Issue number | 1-2 |
| Pages (from-to) | 287-319 |
| Number of pages | 32 |
| ISSN | 0890-5401 |
| Publication status | Published - 2000 |