Assumption---Commitment Support for CSP Model Checking

TL;DR: This work presents a simple formulation of Assumption–Commitment reasoning using CSP (Communicating Sequential Processes), and describes proof rules that allow derivation of assumption–commitment style properties of a composite system from such properties of its components, given appropriate side conditions.

Abstract: We present a simple formulation of Assumption---Commitment reasoning using CSP (Communicating Sequential Processes). An assumption---commitment style property of a process SYS takes the form $COM \sqsubseteq SYS \| ASS $ , for `assumption' and `commitment' processes ASS and COM. We describe proof rules that allow derivation of assumption---commitment style properties of a composite system from such properties of its components, given appropriate side conditions. Most of the rules have a superficially appealing `homomorphic' quality: the overall assumption and commitment processes are composed similarly to the overall system. We also give a `non-homomorphic' rule that corresponds quite well to classical assumption---commitment rules. Antecedants and side conditions can be expressed as refinements and checked separately by the refinement-style model checker FDR. Examples illustrate application of our theory.