Existential MSO over two successors is strictly weaker than over linear orders
نویسندگان
چکیده
منابع مشابه
Existential MSO over two successors is strictly weaker than over linear orders
As is well-known a language of finite words, considered as labeled linear orders, is definable in monadic second-order logic (MSO) iff it is definable in the existential fragment of MSO, that is the quantifier alternation hierarchy collapses. Even more, it does not make a difference if we consider existential MSO over a linear order or a successor relation only. In this note we show that somewh...
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ژورنال
عنوان ژورنال: Theoretical Computer Science
سال: 2009
ISSN: 0304-3975
DOI: 10.1016/j.tcs.2009.04.019