Idempotent Anti-unification

0533995 - ÚI 2021 US eng J - Článek v odborném periodiku
Cerna, David M. - Kutsia, T.
Idempotent Anti-unification.
ACM Transactions on Computational Logic. Roč. 21, č. 2 (2020), č. článku 10. ISSN 1529-3785. E-ISSN 1557-945X
Klíčová slova: unification * Anti-unification * generalization * idempotence * regular tree grammar
Impakt faktor: 0.625, rok: 2020

In this article, we address two problems related to idempotent anti-unification. First, we show that there exists an anti-unification problem with a single idempotent symbol that has an infinite minimal complete set of generalizations. It means that anti-unification with a single idempotent symbol has infinitary or nullary generalization type, similar to anti-unification with two idempotent symbols, shown earlier by Loic Pottier. Next, we develop an algorithm that takes an arbitrary idempotent anti-unification problem and computes a representation of its solution set in the form of a regular tree grammar. The algorithm does not depend on the number of idempotent function symbols in the input terms. The language generated by the grammar is the minimal complete set of generalizations of the given anti-unification problem, which implies that idempotent anti-unification is infinitary.
Trvalý link: http://hdl.handle.net/11104/0312217