Synchrony vs Causality in the Asynchronous Pi-Calculus

TL;DR

This paper investigates whether synchronous interactions in the pi-calculus can be implemented using only asynchronous interactions, revealing fundamental limitations under certain minimal conditions.

Contribution

It proves that, under minimal compositional and correctness-preserving conditions, synchronous interactions cannot be encoded into asynchronous ones without adding causal dependencies.

Findings

Synchronous and asynchronous pi-calculus interactions are fundamentally incompatible under certain conditions.

Encoding synchronous interactions asynchronously requires introducing additional causal dependencies.

The study clarifies the limitations of implementing synchronous communication in asynchronous process calculi.

Abstract

We study the relation between process calculi that differ in their either synchronous or asynchronous interaction mechanism. Concretely, we are interested in the conditions under which synchronous interaction can be implemented using just asynchronous interactions in the pi-calculus. We assume a number of minimal conditions referring to the work of Gorla: a "good" encoding must be compositional and preserve and reflect computations, deadlocks, divergence, and success. Under these conditions, we show that it is not possible to encode synchronous interactions without introducing additional causal dependencies in the translation.