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We explore the potentially "off-by-one" nature of the definitions of counting (#P versus #NP), difference (DP versus DNP), and unambiguous (UP versus UNP; FewP versus FewNP) classes, and make suggestions as to logical approaches in each case. We discuss the strangely differing representations that oracle and predicate models give for counting classes, and(More)
We consider the following optimization problem for UMTS networks: For a specified teletraffic demand and possible base station locations, choose positions for base stations such that<ul><li>the construction costs are below a given limit, </li><li>as much teletraffic as possible is supplied, </li><li>the ongoing costs are minimal, and </li><li>the intra-cell(More)
In a seminal paper from 1985, Sistla and Clarke showed that the model-checking problem for Linear Temporal Logic (LTL) is either NP-complete or PSPACE-complete, depending on the set of temporal operators used. If in contrast, the set of propositional operators is restricted, the complexity may decrease. This article systematically studies the model-checking(More)
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(More)
A binary sequence A = A(0)A(1). .. is called infinitely often (i.o.) Turing-autore-ducible if A is reducible to itself via an oracle Turing machine that never queries its oracle at the current input, outputs either A(x) or a don't-know symbol on any given input x, and outputs A(x) for infinitely many x. If in addition the oracle Turing machine terminates on(More)
The complexity of various problems in connection with Boolean constraints, like, for example, quantified Boolean constraint satisfaction, have been studied recently. Depending on what types of constraints may be used, the complexity of such problems varies. A very interesting observation of the recent past has been that the thus derived classification of(More)