Practical Alternating Parity Tree Automata Model Checking of Higher-Order Recursion Schemes

Abstract

Higher-order (HO) model checking is the problem of deciding whether the tree generated by a higher-order recursion scheme (HORS) is accepted by an alternating parity tree automaton (APT). HO model checking has been shown to be decidable by Ong and recently applied to automated program verification. Practical HO model checkers have been, however, developed only for subclasses of APT such as trivial tree automata and weak APT. In this paper, we develop a practical model checking algorithm for the full class of APT, and implement an APT model checker for HORS. To our knowledge, this is the first model checker for HORS that can deal with the full class of APT. We also discuss its applications to program verification.