Abstract. For deterministic tree automata, classical hierarchies, like MostowskiRabin (or index) hierarchy, Borel hierarchy, or Wadge hierarchy, are known to be decidable. However,...
Two-way alternating automata were introduced by Vardi in order to study the satisfiability problem for the modal µ-calculus extended with backwards modalities. In this paper, we ...
In this paper we generalize the contraction method, originally proposed by Elgot and Rabin and later extended by Carton and Thomas, from labeled linear orderings to colored determ...