期刊名称：Electronic Colloquium on Computational Complexity
印刷版ISSN：1433-8092
出版年度：1997
卷号：1997
出版社：Universität Trier, Lehrstuhl für Theoretische Computer-Forschung
摘要：Pin & Weil [PW95] characterized the automata of existentially
first-order definable languages. We will use this result for the following
characterization of the complexity class NP. Assume that the
Polynomial-Time Hierarchy does not collapse. Then a regular language
L characterizes NP as an unbalanced polynomial-time leaf language
if and only if L is existentially but not quantifierfree definable
in FO[<,min,max,-1,+1].
