A Playful Glance at Hierarchical Questions for Two-Way Alternating Automata
نویسندگان
چکیده
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 present a very simple proof by way of Wadge games of the strictness of the hierarchy of Motowski indices of two-way alternating automata over trees.
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