Tree Automata with Equality Constraints Modulo Equational Theories
Résumé
This paper presents new classes of tree automata combining automata with equality test and automata modulo equational theories. These tree automata are obtained by extending the standard Horn clause representations with equational conditions and rewrite systems. We show in particular that a generalized membership problem (embedding the emptiness problem) is decidable by proving that the saturation of tree automata presentations with suitable paramodulation strategies terminates. We sketch an application of these tree automata classes to the reachability problem for a fragment of the applied pi-calculus.