On Asynchrony and Reversibility in CCS
This study addresses the theoretical gap in reversible process calculi, which are largely confined to synchronous settings, by investigating the integration of asynchronous communication with reversible computation. We propose CCSa, an asynchronous variant of CCS, along with its reversible extension rCCSa. Building upon the Phillips-Ulidowski framework and Lanese’s axiomatic system, our approach employs unique key annotations to explicitly model the generation and consumption of message events, thereby enabling computation rollback that preserves causal dependencies. This work makes a pioneering contribution by introducing reversible semantics into asynchronous CCS, establishing a causally consistent reversible model. Furthermore, we rigorously prove that rCCSa satisfies causal consistency, ensuring that computations can be precisely rolled back to causally equivalent states. These results fill a critical theoretical void in the field of reversible concurrent computation.