Abstract
Nominal Logic is an extension of first-order logic with equality, name-binding, name-swapping, and freshness of names. Contrarily to higher-order logic, bound variables are treated as atoms, and only free variables are proper unknowns in nominal unification. This allows “variable capture”, breaking a fundamental principle of lambda-calculus. Despite this difference, nominal unification can be seen from a higher-order perspective. From this view, we show that nominal unification can be reduced to a particular fragment of higher-order unification problems: higher-order patterns unification. This reduction proves that nominal unification can be decided in quadratic deterministic time.
This research has been partially founded by the CICYT research project TIN2007-68005-C04-01/02/03.
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
Calvès, C., Fernández, M.: Implementing nominal unification. ENTCS 176(1), 25–37 (2007)
Cheney, J.: Relating higher-order pattern unification and nominal unification. In: Proc. of the 19th Int. Work on Unification, UNIF 2005, pp. 104–119 (2005)
Clouston, R.A., Pitts, A.M.: Nominal equational logic. ENTCS 1496, 223–257 (2007)
Cheney, J., Urban, C.: α-prolog: A logic programming language with names, binding and α-equivalence. In: Demoen, B., Lifschitz, V. (eds.) ICLP 2004. LNCS, vol. 3132, pp. 269–283. Springer, Heidelberg (2004)
Dowek, G.: Higher-order unification and matching. Handbook of automated reasoning, pp. 1009–1062 (2001)
Fernández, M., Gabbay, M.: Nominal rewriting with name generation: abstraction vs. locality. In: Proc. of the 7th Int. Conf. on Principles and Practice of Declarative Programming, PPDP 2005, pp. 47–58 (2005)
Fernández, M., Gabbay, M.: Nominal rewriting. Information and Computation 205(6), 917–965 (2007)
Gabbay, M., Cheney, J.: A sequent calculus for nominal logic. In: Proc. of the 19th Symp. on Logic in Computer Science, LICS 2004, pp. 139–148 (2004)
Goldfarb, W.D.: The undecidability of the second-order unification problem. Theoretical Computer Science 13, 225–230 (1981)
Gabbay, M., Pitts, A.M.: A new approach to abstract syntax involving binders. In: Proc. of the 14th Symp. on Logic in Computer Science, LICS 1999, pp. 214–224 (1999)
Levy, J.: Decidable and undecidable second-order unification problems. In: Nipkow, T. (ed.) RTA 1998. LNCS, vol. 1379, pp. 47–60. Springer, Heidelberg (1998)
Lucchesi, C.L.: The undecidability of the unification problem for third-order languages. Technical Report CSRR 2059, Dept. of Applied Analysis and Computer Science, Univ. of Waterloo (1972)
Levy, J., Veanes, M.: On the undecidability of second-order unification. Information and Computation 159, 125–150 (2000)
Miller, D.: A logic programming language with lambda-abstraction, function variables, and simple unification. J. of Logic and Computation 1(4), 497–536 (1991)
Nipkow, T.: Functional unification of higher-order patterns. In: Proc. of the 8th Symp. on Logic in Computer Science, LICS 1993, pp. 64–74 (1993)
Pitts, A.M.: Nominal logic: A first order theory of names and binding. In: Kobayashi, N., Pierce, B.C. (eds.) TACS 2001. LNCS, vol. 2215, pp. 219–242. Springer, Heidelberg (2001)
Pitts, A.M.: Nominal logic, a first order theory of names and binding. Information and Computation 186, 165–193 (2003)
Qian, Z.: Unification of higher-order patterns in linear time and space. J. of Logic and Computation 6(3), 315–341 (1996)
Urban, C., Cheney, J.: Avoiding equivariance in alpha-prolog. In: Urzyczyn, P. (ed.) TLCA 2005. LNCS, vol. 3461, pp. 401–416. Springer, Heidelberg (2005)
Urban, C., Pitts, A.M., Gabbay, M.J.: Nominal unification. In: Baaz, M., Makowsky, J.A. (eds.) CSL 2003. LNCS, vol. 2803, pp. 513–527. Springer, Heidelberg (2003)
Urban, C., Pitts, A.M., Gabbay, M.J.: Nominal unification. Theoretical Computer Science 323, 473–497 (2004)
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2008 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Levy, J., Villaret, M. (2008). Nominal Unification from a Higher-Order Perspective. In: Voronkov, A. (eds) Rewriting Techniques and Applications. RTA 2008. Lecture Notes in Computer Science, vol 5117. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-70590-1_17
Download citation
DOI: https://doi.org/10.1007/978-3-540-70590-1_17
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-70588-8
Online ISBN: 978-3-540-70590-1
eBook Packages: Computer ScienceComputer Science (R0)