Hostname: page-component-848d4c4894-2pzkn Total loading time: 0 Render date: 2024-06-02T09:10:59.153Z Has data issue: false hasContentIssue false

On polynomial time computation over unordered structures

Published online by Cambridge University Press:  12 March 2014

Andreas Blass
Affiliation:
Mathematics Department, University of Michigan, Ann Arbor, MI 48109-1109, USA, E-mail: ablass@umich.edu
Yuri Gurevich
Affiliation:
Microsoft Research, One Microsoft Way, Redmond. WA 98052, USA, E-mail: gurevich@microsoft.com
Saharon Shelah
Affiliation:
Institute of Mathematics, Hebrew University of Jerusalem, Givat Ram, 91904 Jerusalem, Israel Mathematics Department, Rutgers University, New Brunswick, NJ 08903, USA, E-mail: shelah@math.huji.ac.il

Abstract

This paper is motivated by the question whether there exists a logic capturing polynomial time computation over unordered structures. We consider several algorithmic problems near the border of the known, logically defined complexity classes contained in polynomial time. We show that fixpoint logic plus counting is stronger than might be expected, in that it can express the existence of a complete matching in a bipartite graph. We revisit the known examples that separate polynomial time from fixpoint plus counting. We show that the examples in a paper of Cai, Fürer, and Immerman, when suitably padded, are in choiceless polynomial time yet not in fixpoint plus counting. Without padding, they remain in polynomial time but appear not to be in choiceless polynomial time plus counting. Similar results hold for the multipede examples of Gurevich and Shelah, except that their final version of multipedes is, in a sense, already suitably padded. Finally, we describe another possible candidate, involving determinants, for the task of separating polynomial time from choiceless polynomial time plus counting.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 2002

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

[1]Abiteboul, S. and Vianu, V., Generic computation and its complexity, Proceedings of the 23rd ACM Symposium on Theory of Computing, 1991, pp. 209219.Google Scholar
[2]Blass, A. and Gurevich, Y., Strong extension axioms and Shelah's zero-one law for choiceless polynomial time, to appear.Google Scholar
[3]Blass, A., Equivalence relations, invariants, and normal forms, SIAM Journal on Computing, vol. 13 (1984), pp. 682689.CrossRefGoogle Scholar
[4]Blass, A., Equivalence relations, invariants, and normal forms, II, Logic and Machines: Decision Problems and Complexity (Börger, E., Hasenjaeger, G., and Rödding, D., editors), Lecture Notes in Computer Science, vol. 171, Springer-Verlag, 1984, pp. 2442.CrossRefGoogle Scholar
[5]Blass, A., Gurevich, Y., and den Bussche, J. V., Abstract state machines and computationally complete query languages, Information and Computation, An abridged version appeared in Abstract State Machines: Theory and Applications, (Gurevich, Y., Kutter, P., Odersky, M., and Thiele, L., editors). Lecture Notes in Computer Science, vol. 1912, Spinger-Verlag, 2000, pp. 2233.Google Scholar
[6]Blass, A., Gurevich, Y., and Shelah, S., Choiceless polynomial time, Annals of Pure and Applied Logic, vol. 100 (1999), pp. 141187.CrossRefGoogle Scholar
[7]Bollobás, B., Graph Theory: An Introductory Course, Springer-Verlag, 1979.CrossRefGoogle Scholar
[8]Cai, J. Y., Fürer, M., and Immerman, N., An optimal lower bound on the number of variables for graph identification, Combinatorica, vol. 12 (1992), pp. 389410.CrossRefGoogle Scholar
[9]Chandra, A. and Harel, D., Structure and complexity of relational queries, Journal of Computer and System Sciences, vol. 25 (1982), pp. 99128.CrossRefGoogle Scholar
[10]Gire, F. and Hoang, H. A, An extension of fixpoint logic with a symmetry-based choice construct, Information and Computation, vol. 144 (1998), pp. 4065.CrossRefGoogle Scholar
[11]Grädel, E. and Gurevich, Y., Metafinite model theory, Information and Computation, vol. 140 (1998), pp. 2681.CrossRefGoogle Scholar
[12]Gurevich, Y., Logic and the challenge of computer science, Current trends in theoretical computer science (Börger, E., editor). Computer Science Press, 1988, pp. 157.Google Scholar
[13]Gurevich, Y., Evolving algebras 1993: Lipari guide, Specification and validation methods (Börger, E., editor), Oxford University Press, 1995, pp. 936.Google Scholar
[14]Gurevich, Y., From invariants to canonization, Bulletin of the European Association on Theoretical Computer Science, vol. 63 (1997), Also as Logic in Computer Science, in Current trends in theoretical computer science: Entering the 21st century, (Paun, G., Rozenberg, G. and Salomaa, A., editors). World Scientific, 2001, pp. 233436.Google Scholar
[15]Gurevich, Y. and Shelah, S., On finite rigid structures, this Journal, vol. 61 (1996), pp. 549562.Google Scholar
[16]Huggins, J. K., ASM Michigan Web page, http://www.eecs.umich.edu/gasm/.Google Scholar
[17]Immerman, N., Relational queries computable in polynomial time, Information and Control, vol. 68 (1986), pp. 86104.CrossRefGoogle Scholar
[18]Otto, M., Bounded variable logics and counting: A study in finite models, Lecture Notes in Logic, vol. 9, Springer-Verlag, 1997.CrossRefGoogle Scholar
[19]Shelah, S., Choiceless polynomial time logic: Inability to express, Computer Science Logic 2000 (Clote, P. and Schwichtenberg, H., editors), Lecture Notes in Computer Science, vol. 1862, Springer-Verlag, 2000, paper number 634, pp. 72125.Google Scholar
[20]Vardi, M., The complexity of relational query languages, Proceedings of the 14th ACM Symposium on Theory of Computing, 1982, pp. 137146.Google Scholar