Abstract
Lutz (SIAM J. Comput. 24(6), 1170–1189, 1995) proposed the following generalization of hardness: While a problem A is hard for a complexity class C if all problems in C can be reduced to A, Lutz calls a problem weakly hard if a nonnegligible part of the problems in C can be reduced to A. For the linear exponential time class E = DTIME(2lin), Lutz formalized these ideas by introducing a resource-bounded (pseudo) measure on this class and by saying that a subclass of E is negligible if it has measure 0 in E. In this paper we introduce two new weak hardness notions for E – E-nontriviality and strongly E-nontriviality. They generalize Lutz’s weak hardness notion for E, but are much simpler conceptually. Namely, a set A is E-nontrivial if, for any k ≥ 1, there is a set Bk ∈E which can be reduced to A (by a polynomial time many-one reduction) and which cannot be computed in time O(2kn), and a set A is strongly E-nontrivial if the set Bk can be chosen to be almost everywhereO(2kn)-complex, i.e. if Bk can be chosen such that any algorithm that computes Bk runs for more than 2k|x| steps on all but finitely many inputs x.
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References
Ambos-Spies, K.: Randomness relativizations, and polynomial reducibilities. Structure in complexity theory (Berkeley, Calif., 1986), 23–34, Lecture Notes in Comput Sci., vol. 223. Springer, Berlin (1986)
Ambos-Spies, K.: Minimal pairs for polynomial time reducibilities. Computation theory and logic, 1–13, Lecture Notes in Comput Sci., vol. 270. Springer, Berlin (1987)
Ambos-Spies, K.: Honest polynomial time reducibilities and the P =? NP problem. J. Comput. Syst. Sci. 39(3), 250–281 (1989)
Ambos-Spies, K.: Resource-bounded genericity. Computability, enumerability, unsolvability, 1–59, London Math. Soc. Lecture Note Ser., vol. 224. Cambridge Univ. Press, Cambridge (1996)
Ambos-Spies, K.: Polynomial time reducibilities and degrees. Handbook of computability theory, 683–705, Stud. Logic Found. Math., 140, North-Holland, Amsterdam (1999)
Ambos-Spies, K, Bakibayev, T.: Weak completeness notions for exponential time. Automata, languages and programming. Part I, 503–514, Lecture Notes in Comput Sci., vol. 6198. Springer, Berlin (2010)
Ambos-Spies, K., Bakibayev, T.: Nontriviality for exponential time w.r.t. weak reducibilities. Theoret. Comput. Sci. 494, 2–12 (2013)
Ambos-Spies, K., Bakibayev, T.: Comparing nontriviality for. E and EXP. Theory Comput. Syst. 51(1), 106–122 (2012)
Ambos-Spies, K., Mayordomo, E., Zheng, X.: A comparison of weak completeness notions. In: Proceedings of the 11th annual IEEE conference on computational complexity, 171–178 (1996)
Ambos-Spies, K., Terwijn, S.A., Zheng, X.: Resource bounded randomness and weakly complete problems. Theoret. Comput. Sci. 172(1-2), 195–207 (1997)
Balcázar, J., Díaz, J., Gabarró J.: Structural complexity. I. Second edition. Texts in Theoretical Computer Science. An EATCS Series. Springer, Berlin (1995)
Balcázar, J.L., Díaz, J., Gabarró, J.: Structural complexity. II. EATCS monographs on theoretical computer science, vol. 22. Springer, Berlin (1990)
Buhrman, H., Mayordomo, E.: An excursion to the Kolmogorov random strings. Tenth Annual Conference on Structure in Complexity Theory (Minneapolis, MN. J. Comput. Syst. Sci. 54(3), 393–399 (1997)
Geske, J.G., Huỳnh, D.T., Selman, A.L.: A hierarchy theorem for almost everywhere complex sets with application to polynomial complexity degrees. STACS 87 (Passau, 1987), 125–135, Lecture Notes in Comput Sci., 247. Springer, Berlin (1987)
Juedes, D.W., Lutz, J.H.: Weak completeness in E and E2. Theoret. Comput. Sci. 143(1), 149–158 (1995)
Ladner, R.E.: On the structure of polynomial time reducibility. J. Assoc. Comput. Mach. 22, 155–171 (1975)
Li, M., Vitányi, P.: An introduction to Kolmogorov complexity and its applications Graduate texts in computer science. 2nd edn. Springer-Verlag, New York (1997)
Lutz, J.H.: Weakly hard problems. SIAM J. Comput. 24(6), 1170–1189 (1995)
Lutz, J.H., Mayordomo, E.: Measure stochasticity, and the density of hard languages. SIAM J. Comput. 23(4), 762–779 (1994)
Watanabe, O.: A comparison of polynomial time completeness notions. Theoret. Comput. Sci. 54(2-3), 249–265 (1987)
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We thank the referees for their very helpful comments and suggestions.
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The authors were supported in part by the Ministry of Education and Science of Kazakhstan research grant number AP05131579. Some results of this paper have been presented at the ICALP Conference, Bordeaux, in 2010 [6].
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Ambos-Spies, K., Bakibayev, T. Weak Completeness Notions for Exponential Time. Theory Comput Syst 63, 1388–1412 (2019). https://doi.org/10.1007/s00224-019-09920-4
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DOI: https://doi.org/10.1007/s00224-019-09920-4