Unified Decision Procedures for Regular Expression Equivalence

Tobias Nipkow, Dmitriy Traytel

We formalize a unified framework for verified decision procedures for regular expression equivalence. Five recently published formalizations of such decision procedures (three based on derivatives, two on marked regular expressions) can be obtained as instances of the framework. We discover that the two approaches based on marked regular expressions, which were previously thought to be the same, are different, and one seems to produce uniformly smaller automata. The common framework makes it possible to compare the performance of the different decision procedures in a meaningful way.



author={Tobias Nipkow and Dmitriy Traytel},
title={Unified Decision Procedures for Regular Expression Equivalence},
booktitle={Interactive Theorem Proving (ITP 2014)},
editor={R. Gamboa and G. Klein},
Isabelle theories in the Archive of Formal Proofs