The density and complexity of polynomial cores for intractable sets

Q4 Mathematics
Pekka Orponen, Uwe Schöning
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引用次数: 46

Abstract

Let A be a recursive problem not in P. Lynch has shown that A then has an infinite recursive polynomial complexity core. This is a collection C of instances of A such that every algorithm deciding A needs more than polynomial time almost everywhere on C. We investigate the complexity of recognizing the instances in such a core, and show that every recursive problem A not in P has an infinite core recognizable in subexponential time. We further study how dense the core sets for A can be, under various assumptions about the structure of A. Our main results in this direction are that if PNP, then NP-complete problems have polynomially nonsparse cores recognizable in subexponential time, and that EXPTIME-complete problems have cores of exponential density recognizable in exponential time.

棘手集多项式核的密度和复杂度
设A是一个不在p中的递归问题,Lynch证明了A有一个无限递归多项式复杂度核。这是a的实例集合C,使得几乎在C上任何地方决定a的算法都需要超过多项式的时间。我们研究了在这样一个核中识别实例的复杂性,并证明了不在P中的每个递归问题a都有一个在次指数时间内可识别的无限核。我们进一步研究了在关于A结构的各种假设下,A的核集的密度。我们在这个方向上的主要结果是,如果P≠NP,那么NP完全问题具有在次指数时间内可识别的多项式非稀疏核,exptime完全问题具有在指数时间内可识别的指数密度核。
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来源期刊
信息与控制
信息与控制 Mathematics-Control and Optimization
CiteScore
1.50
自引率
0.00%
发文量
4623
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