A Variant of Higher-Order Anti-Unification

Abstract

We present a rule-based Huet's style anti-unification algorithm for simply-typed lambda-terms in η-long -normal form, which computes a least general higher-order pattern generalization. For a pair of arbitrary terms of the same type, such a generalization always exists and is unique modulo α-equivalence and variable renaming. The algorithm computes it in cubic time within linear space. It has been implemented and the code is freely available. © Alexander Baumgartner, Temur Kutsia, Jordi Levy, and Mateu Villaret; licensed under Creative Commons License CC-BY 24th International Conference on Rewriting Techniques and Applications (RTA'13).This research has been partially supported by the projects HeLo (TIN2012-33042) and TASSAT (TIN2010-20967-C04-01), by the Austrian Science Fund (FWF) with the project SToUT (P 24087-N18) and by the Generalitat de Catalunya with the grant AGAUR 2009-SGR-1434.Peer Reviewe