Abstract
Modular properties of term rewriting systems, i.e. properties which are preserved under disjoint unions, have attracted an increasing attention within the last few years. Whereas confluence is modular this does not hold true in general for termination. By means of a careful analysis of potential counterexamples we prove the following abstract result. Whenever the disjoint union ℛ1 ⊕ ℛ2 of two (finitely branching) terminating term rewriting systems ℛ1, ℛ2 is non-terminating, then one of the systems, say ℛ1, enjoys an interesting (undecidable) property, namely it is not termination preserving under non-deterministic collapses, i.e. ℛ1 ⊕ {itG(x, y)→ x, G(x, y) → y} is non-terminating, and the other system ℛ2 is collapsing, i.e. contains a rule with a variable right hand side. This result generalizes known sufficient criteria for modular termination of rewriting and provides the basis for a couple of derived modularity results. Furthermore, we prove that the minimal rank of potential counterexamples in disjoint unions may be arbitrarily high which shows that interaction of systems in such disjoint unions may be very subtle. Finally, extensions and generalizations of our main results in various directions are discussed. In particular, we show how to generalize the main results to some restricted form of non-disjoint combinations of term rewriting systems, namely for ‘combined systems with shared constructors’.
Similar content being viewed by others
Explore related subjects
Discover the latest articles, news and stories from top researchers in related subjects.References
Dershowitz, N.: A note on simplification orderings. Information Processing Letters,9(5), 212–215 (1979)
Dershowitz, N.: Orderings for term-rewriting systems. Theoret Comput Sci 279–301 (1982)
Dershowitz, N.: Termination of rewriting. J. Symbolic Comput.3(1), 69–116 (1987)
Dershowitz, N., Jouannaud, J.-P.: Rewrite systems. In: van Leeuwen, J. (ed.). Formal models and semantics, Handbook of Theoretical Computer Science, vol. B, Chap. 6, pp. 243–320. Elsevier, The MIT Press 1990
Drosten, K.: Termersetzungssysteme. Informatik-Fachberichte vol. 210. Berlin, Heidelberg, New York: Springer 1989
Ganzinger, H., Giegerich, R.: A note on termination in combinations of heterogeneous term rewriting systems. Bull. European Assoc. Theoret. Comput. Sci.31, 22–28 (1987)
Gramlich, B.: A structural analysis of modular termination of term rewriting systems. SEKI Report SR-91-15, Dept. of Comp. Science, Univ. of Kaiserslautern, 1991
Gramlich, B.: Generalized sufficient conditions for modular termination of rewriting. In: Kirchner, H., Levi, G. (eds). Proc. of 3rd Int. Conf. on Algebraic and Logic Programming, Pisa, Italy, vol. 632. Lecture Notes in Computer Science, pp. 53–68. Berlin, Heidelberg, New York: Springer 1992
Gramlich, B.: Relating innermost, weak, uniform and modular termination of term rewriting systems. In: Voronkov, A. (ed.) International Conference on Logic Programming and Automated Reasoning, St. Petersburg, vol.624. Lecture Notes in Artificial Intelligence, pp. 285–296. Berlin, Heidelberg, New York: Springer 1992
Gramlich, B.: Sufficient conditions for modular termination of conditional term rewriting systems. In: Rusinowitch, M., Remy, J. L. (eds) Proc. of the 3rd International Workshop on Conditional Term Rewriting Systems, Pont-à-Mousson, vol.656. Lecture Notes in Computer Science, pp. 128–142. Berlin, Heidelberg, New York: Springer 1992
Huet, G., Lankford, D.: On the uniform halting problem for term rewriting systems. Technical Report 283, INRIA, 1978
Huet, G., Oppen, D. C.: Equations and rewrite rules: A survey. In: Ronald V. Book (ed.) Formal Languages, Perspectives And Open Problems, pp. 349–405. New York: Academic Press 1980
Klop, J. W.: Term rewriting systems. In: Abramsky, S., Gabbay, D., Maibaum, T. (eds). Handbook of Logic in Computer Science, volI. Oxford: University Press 1990
Kurihara, M., Kaji, I.: Modular term rewriting systems and the termination. Inf. Proc. Lett.34, 1–4 (1990)
Kurihara, M., Ohuchi, A.: Modularity of simple termination of term rewriting systems. J. IPS, Jpn34, 632–642 (1990)
Kurihara, M., Ohuchi, A.: Modularity of simple termination of term rewriting systems with shared constructors. Technical Report SF-36, Hokkaido University, Sapporo, 1990. Also in TCS103, 273–282 (1992)
Middeldorp, A.: Modular aspects of properties of term rewriting systems related to normal forms. In: Dershowitz, N. (ed.) Proceedings of the 3rd International Conference on Rewriting Techniques and Applications, vol.335. Lecture Notes in Computer Science, pp. 263–277. Berlin, Heidelberg, New York: Springer 1989
Middeldorp, A.: A sufficient condition for the termination of the direct sum of term rewriting systems. In: Proceedings of the 4th IEEE Symposium on Logic in Computer Science, pp. 396–401. Pacific Grove 1989
Middeldorp, A.: Termination of disjoint unions of conditional term rewriting systems. Technical Report CS-R8959, Centre for Mathematics and Computer Science, Amsterdam 1989
Middeldorp, A.: Confluence of the disjoint union of conditional term rewriting systems. In: Kaplan, S., Okada, M. (eds). Proc. of the 2nd Int. Workshop on Conditional and Typed Rewriting Systems, vol.516. Lecture Notes in Computer Science, pp. 295–306. Berlin, Heidelberg, New York: Springer 1990
Middeldorp, A.: Modular Properties of Term Rewriting Systems. PhD thesis, Free University, Amsterdam 1990
Middeldorp, A.: Completeness of combinations of conditional constructor systems. In: Rusinowitch, M., Remy, J. L. (eds). Proc. of the 3rd International Workshop on Conditional Term Rewriting Systems, Pont-à-Mousson, vol.656 Lecture Notes in Computer Science, pp. 82–96. Berlin, Heidelberg, New York: Springer 1992
Middeldorp, A., Toyama, Y.: Completeness of combinations of constructor systems. In: Book, R. V. (ed). Proc. of the 4th Int. Conf. on Rewriting Techniques and Applications, vol.488. Lecture Notes in Computer Science, pp. 174–187. Berlin, Heidelberg, New York: Springer 1991
Ohlebusch, E.: Combinations of simplifying conditional term rewriting systems. In: Rusinowitch, M., Remy, J. L. (eds). Proc. of the 3rd International Workshop on Conditional Term Rewriting Systems, Pont-à-Mousson, vol.656. Lecture Notes in Computer Science, pp. 113–127. Berlin, Heidelberg, New York: Springer 1992
Ohlebusch, E.: A note on simple termination of infinite term rewriting systems. Technical Report 7, Univ. of Bielefeld 1992
Rusinowitch, M.: On termination of the direct sum of term rewriting systems. Inf. Proc. Lett.26, 65–70 (1987)
Seifert, R.: Fachbereich Informatik, Univ. Bremen, personal communication, July 1992
Toyama, Y.: Counterexamples to termination for the direct sum of term rewriting systems. Inf. Proc. Lett.25, 141–143 (1987)
Toyama, Y.: On the Church-Rosser property for the direct sum of term rewriting systems. J. ACM34(1), 128–143 (1987)
Toyama, Y., Klop, J. W., Barendregt, H. P.: Termination for the direct sum of left-linear term rewriting systems. In: Dershowitz, N. (ed.) Proc. of the 3rd Int. Conf. on Rewriting Techniques and Applications, vol.355. Lecture Notes in Computer Science, pp. 477–491. Berlin, Heidelberg, New York: Springer 1989
Zantema, H.: Termination of term rewriting by interpretation. In: Rusinowitch, M., Remy, J. L. (eds) Proc. of the 3rd International Workshop on Conditional Term Rewriting Systems, Pont-à-Mousson, vol.656. Lecture Notes in Computer Science, pp. 155–167. Berlin, Heidelberg, New York: Springer 1992
Author information
Authors and Affiliations
Additional information
This research was supported by the ‘Deutsche Forschungsgemeinschaft, SFB 314 (D4-Projekt)’.
Rights and permissions
About this article
Cite this article
Gramlich, B. Generalized sufficient conditions for modular termination of rewriting. AAECC 5, 131–158 (1994). https://doi.org/10.1007/BF01190827
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01190827