LINDSTRÖM QUANTIFIERS AND LEAF LANGUAGE DEFINABILITY
1998 ◽
Vol 09
(03)
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pp. 277-294
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We introduce second-order Lindström quantifiers and examine analogies to the concept of leaf language definability. The quantifier structure in a second-order sentence defining a language and the quantifier structure in a first-order sentence characterizing the appropriate leaf language correspond to one another. Under some assumptions, leaf language definability and definability with second-order Lindström quantifiers may be seen as equivalent. Along the way we tighten the best up to now known leaf language characterization of the classes of the polynomial time hierarchy and give a new model-theoretic characterization of PSPACE.
2001 ◽
Vol 11
(1)
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pp. 117-153
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2012 ◽
Vol 55
(3)
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pp. 632-645
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