Certifying Confluence of Quasi-Decreasing Strongly Deterministic Conditional Term Rewrite Systems
Christian Sternagel, Thomas Sternagel · Lecture notes in computer science · 2017
We formalize a confluence criterion for the class of quasi-decreasing strongly deterministic conditional term rewrite systems in Isabelle/HOL: confluence follows if all conditional critical pairs are joinable. However, quasi-decreasingness, strong determinism, and joinability of conditional critical pairs are all undecidable in general. Therefore, we also formalize sufficient criteria for those properties, which we incorporate into the general purpose certifier CeTA as well as the confluence checker ConCon for conditional term rewrite systems.