The Hybrid µ-Calculus

Abstract

Abstract. We present an ExpTime decision procedure for the full µ-Calculus (including converse programs) extended with nominals and a universal program, thus devising a new, highly expressive ExpTime logic. The decision procedure is based on tree automata, and makes explicit the problems caused by nominals and how to overcome them. Roughly speaking, we show how to reason in a logic lacking the tree model property using techniques for logics with the tree model property. The contribution of the paper is two-fold: we extend the family of ExpTime logics, and we present a technique to reason in the presence of nominals. 1