Inspecting Maude Variants with GLINTS

TL;DR

GLINTS is a graphical tool that enhances the exploration and debugging of variant narrowing computations in Maude, facilitating formal reasoning and analysis of theories with the finite variant property.

Contribution

The paper introduces GLINTS, a novel graphical system that supports detailed exploration, verification, and inspection of variant narrowing processes in Maude, improving understanding and debugging capabilities.

Findings

Supports detection of finite variant property in theories

Enables thorough exploration of variant narrowing computations

Provides automatic checks for node embedding and closedness

Abstract

This paper introduces GLINTS, a graphical tool for exploring variant narrowing computations in Maude. The most recent version of Maude, version 2.7.1, provides quite sophisticated unification features, including order-sorted equational unification for convergent theories modulo axioms such as associativity, commutativity, and identity (ACU). This novel equational unification relies on built-in generation of the set of 'variants' of a term $t$, i.e., the canonical form of $t \sigma$ for a computed substitution $\sigma$. Variant generation relies on a novel narrowing strategy called 'folding variant narrowing' that opens up new applications in formal reasoning, theorem proving, testing, protocol analysis, and model checking, especially when the theory satisfies the 'finite variant property', i.e., there is a finite number of most general variants for every term in the theory. However, variant narrowing computations can be extremely involved and are simply presented in text format by Maude, often being too heavy to be debugged or even understood. The GLINTS system provides support for (i) determining whether a given theory satisfies the finite variant property, (ii) thoroughly exploring variant narrowing computations, (iii) automatic checking of node 'embedding' and 'closedness' modulo axioms, and (iv) querying and inspecting selected parts of the variant trees. This paper is under consideration for acceptance in TPLP.