A Tentative Approach for the Wadge-Wagner Hierarchy of Regular Tree Languages of Index [0, 2]
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چکیده
We provide a hierarchy of tree languages recognised by nondeterministic parity tree automata with priorities in {0, 1, 2}, whose length exceeds the first fixed point of the ε operation (that itself enumerates the fixed points of x 7→ ω). We conjecture that, up to Wadge equivalence, it exhibits all regular tree languages of index [0, 2].
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تاریخ انتشار 2015