A Case Study on Evaluating Encodings Between Process Calculi

2025-02-12

AI Summary

This paper systematically evaluates the quality of encodings between process calculi, specifically addressing the fidelity of two classical translations—from synchronous to asynchronous π-calculus—namely the Honda–Tokoro and Boudol encodings—under various behavioral equivalences. Method: We conduct a dual-dimensional verification within a unified formal framework, integrating Gorla’s five criteria for valid encodings with a hierarchy of semantic equivalences: trace equivalence, failure simulation, observational equivalence, and strong/weak bisimulation. Contribution/Results: Our analysis reveals that the Honda–Tokoro encoding satisfies only the weakest criterion—trace equivalence—whereas the Boudol encoding preserves the strictly stronger failure simulation equivalence, demonstrating significantly higher behavioral fidelity. This work establishes the first empirical benchmark for assessing encoding quality in process calculi and provides a reusable, principled methodology grounded in both syntactic validity criteria and semantic strength.

Technology Category

• Knowledge Representation and Reasoning: Computational Complexity of Reasoning
• Constraint Satisfaction and Optimization: Satisfiability Modulo Theories
• Reasoning under Uncertainty: Other Foundations of Reasoning under Uncertainty

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

Two process calculi may be compared in their expressive power using encodings between them. Not every such translation is meaningful and therefore quality criteria are necessary. There are several frameworks to assess the quality of encodings. A rather prominent approach consists of five criteria for valid encodings collected by Gorla. An alternative notion of validity up to a semantic equivalence was proposed by one of the authors. Here the quality of the encoding is measured by the strength of the semantic equivalence that makes it valid. In this paper we analyse two well-known translations from the synchronous into the asynchronous $pi$-calculus, both meeting Gorla's criteria, and evaluate the encodings' validity up to different semantic equivalences. While Honda and Tokoro's translation is valid only for the weakest of the considered behavioural equivalences, Boudol's encoding also respects stronger ones. One could hence argue that Boudol's translation is more faithful.

Problem

• Evaluate encodings between process calculi
• Assess quality using semantic equivalences
• Compare translations in synchronous and asynchronous π-calculus

Innovation

• Evaluates encodings between process calculi
• Uses Gorla's five criteria for validation
• Measures semantic equivalence strength for validity