What Is a ‘Good’ Encoding of Guarded Choice?

The pi-calculus with synchronous output and mixed-guarded choices is strictly more expressive than the pi-calculus with asynchronous output and no choice. As a corollary, Palamidessi recently proved that there is no fully compositional encodingfrom the former into the latter that preserves divergence-freedom and symmetries. This paper shows 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 firstand 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 studysuggests that the combination of strong compositionality and divergence-freedom is too strong for more practical purposes

What is a ‘Good’ Encoding of Guarded Choice?

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 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

On Distributed Verification and Verified Distribution

Fokkink, W.J. [Promotor]Pol, J.C. van de [Copromotor

Group-Enhanced Remote Method Invocations

S. All local authors can be reached via e-mail at the address [email protected]. Questions and comments should be addressed to [email protected]. Recent Titles from the UBLCS Technical Report Series 96-16 Fault Tolerance through View Synchrony in Partitionable Asynchronous Distributed Systems, A. Montresor, December 1996. 96-17 A Tutorial on EMPA: A Theory of Concurrent Processes with Nondeterminism, Priorities, Probabilities and Time, M. Bernardo, R. Gorrieri, December 1996 (Revised January 1997). 97-1 Partitionable Group Membership: Specification and Algorithms, O. Babao glu, R. Davoli, A. Montresor, January 1997. 97-2 A Truly Concurrent View of Linda Interprocess Communication, N. Busi, R. Gorrieri, G. Zavattaro, February 1997. 97-3 Knowledge-Level Speech Acts, M. Gaspari, March 1997. 97-4 An Algebra of Actors, M. Gaspari, G. Zavattaro, May 1997. 97-5 On the Turing Equivalence of Linda Coordination Primitives, N. Busi, R. Gorrieri, G. Zavattaro, May 1997 (Revised October 19..