Abstract
We give an algorithm for deciding E-unification problems for linear standard equational theories (linear equations with all shared variables at a depth less than two) and varity 1 goals (linear equations with no shared variables). We show that the algorithm halts in quadratic time for the non-uniform E-unification problem, and linear time if the equational theory is varity 1. The algorithm is still polynomial for the uniform problem. The size of the complete set of unifiers is exponential, but membership in that set can be determined in polynomial time. For any goal (not just varity 1) we give a NEXPTIME algorithm.
This work was supported by NSF grant number CCR-9712388 and ONR grant number N00014-01-1-0435..
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
F. Baader and T. Nipkow. Term Rewriting and All That. Cambridge, 1998.
D. Basin and H. Ganzinger. Automated complexity analysis based on ordered resolution. In J. Association for Computing Machinery 48(1), 70–109, 2001.
H. Comon. Sequentiality, second order monadic logic and tree automata. In Proceedings 10th IEEE Symposium on Logic in Computer Science, LICS’95, IEEE Computer Society Press, 508–517,1995.
H. Comon, M. Haberstrau and J.-P. Jouannaud. Syntacticness, Cycle Syntacticness and shallow theories. In Information and Computation 111(1), 154–191, 1994.
W. Dowling and J. Gallier. Linear-time algorithms for testing the satisfiability of propositional horn formulae. In Journal of Logic Programming 3, 267–284, 1984.
J. Gallier and W. Snyder. Complete sets of transformations for general Eunification. In TCS, vol. 67, 203–260, 1989.
H. Ganzinger. Relating Semantic and Proof-Theoretic Concepts for Polynomial Time Decidability of Uniform Word Problems. In Proceedings 16th IEEE Symposium on Logic in Computer Science, LICS’ 2001, Boston, 2001.
F. Jacquemard. Decidable approximations of term rewriting systems. In H. Ganzinger, ed., Rewriting Techniques and Applications, 7th International Conference, RTA-96, Vol. 1103 of LNCS, Springer, 362–376, 1996.
F. Jacquemard, Ch. Meyer, Ch. Weidenbach. Unification in Extensions of Shallow Equational Theories. In T. Nipkow, ed., Rewriting Techniques and Applications,9th International Conference, RTA-98, Vol. 1379, LNCS, Springer, 76–90, 1998.
C. Kirchner. Computing unification algorithms. In Proceedings of the Fourth Symposium on Logic in Computer Science, Boston, 200–216, 1990.
D. Kozen. Complexity of finitely presented algebras. In Proc. 9th STOC, 164–177,1977.
D. Kozen. Positive first order logic is NP-complete. IBM Journal of Res. Developp., 25(4):327–332, July 1981.
C. Lynch and B. Morawska. Complexity of Linear Standard Theories.http://www.clarkson.edu/~clynch/papers/standard_full.ps/, 2001.
C. Lynch and B. Morawska. Decidability and Complexity of Finitely Closable Linear Equational Theories. In R. Goré, A. Leitsch and T. Nipkow, eds., Automated Reasoning. First International Joint Conference, IJCAR 2001, Vol. 2083 of LNAI,499–513, Springer, 2001.
C. Lynch and B. Morawska. Goal Directed E-Unification. In RTA 12,. A. Middeldorp, LNCS vol. 2051, 231–245, 2001.
D. McAllester. Automated Recognition of Tractability in Inference Relations. In Journal of the ACM, vol.40(2), pp. 284–303, 1993.
A. Middeldorp, S. Okui, T. Ida. Lazy Narrwing: Strong Completeness and Eager Variable Elimination. In Theoretical Computer Science 167(1,2), pp. 95–130, 1996.
R. Nieuwenhuis. Basic paramodulation and decidable theories. (Extended abstract),In Proceedings 11th IEEE Symposium on Logic in Computer Science,LICS’96, IEEE Computer Society Press, 473–482, 1996.
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2001 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Lynch, 1., Morawska, B. (2001). Complexity of Linear Standard Theories. In: Nieuwenhuis, R., Voronkov, A. (eds) Logic for Programming, Artificial Intelligence, and Reasoning. LPAR 2001. Lecture Notes in Computer Science(), vol 2250. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-45653-8_13
Download citation
DOI: https://doi.org/10.1007/3-540-45653-8_13
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-42957-9
Online ISBN: 978-3-540-45653-7
eBook Packages: Springer Book Archive