Parametrized Regular Infinite Games and Higher-Order Pushdown Strategies
Paul H�nsch, Michaela Slaats, Wolfgang Thomas
AIB 2009-18
Given a set $P$ of natural numbers, we consider infinite games where
the winning condition is a regular $\omega$-language parametrized by
$P$. In this context, an $\omega$-word, representing a play, has
letters consisting of three components: The first is a bit indicating
membership of the current position in $P$, and the other two
components are the letters contributed by the two players.
Extending recent work of Rabinovich we study here predicates $P$
where the structure $(\mathbb{N}, +1, P)$ belongs to the pushdown
hierarchy (or ``Caucal hierarchy''). For such a predicate $P$ where
$(\mathbb{N}, +1, P)$ occurs in the $k$-th level of the hierarchy,
we provide an effective determinacy result and show that winning
strategies can be implemented by deterministic level-$k$ pushdown
automata.