skip to main content
article
Free access

Proving termination with multiset orderings

Published: 01 August 1979 Publication History

Abstract

A common tool for proving the termination of programs is the well-founded set, a set ordered in such a way as to admit no infinite descending sequences. The basic approach is to find a termination function that maps the values of the program variables into some well-founded set, such that the value of the termination function is repeatedly reduced throughout the computation. All too often, the termination functions required are difficult to find and are of a complexity out of proportion to the program under consideration.
Multisets (bags) over a given well-founded set S are sets that admit multiple occurrences of elements taken from S. The given ordering on S induces an ordering on the finite multisets over S. This multiset ordering is shown to be well-founded. The multiset ordering enables the use of relatively simple and intuitive termination functions in otherwise difficult termination proofs. In particular, the multiset ordering is used to prove the termination of production systems, programs defined in terms of sets of rewriting rules.

References

[1]
Dijkstra, E.W. A small note on the additive composition of variant functions. Note EWD592, Burroughs Corp., Neunen, The Netherlands, 1976.
[2]
Floyd, R.W. Assigning meanings to programs. Proc. Symp. in Applied Math., Vol. 19, Amer. Math. Soc., Providence, R.I., pp. 19- 32.
[3]
Gentzen, G. New version of the consistency proof for elementary number theory (1938). In The Collected Papers of Gerhart Gentzen, M.E. Szabo, Ed., North-Holland, Amsterdam, 1969, pp. 252-286.
[4]
Gorn, S. Explicit definitions and linguistic dominoes. Proc. Conf. on Syst. and Comptr. Sci., London, Ontario, Sept. 1965, pp. 77-115.
[5]
Iturriaga, R. Contributions to mechanical mathematics. Ph.D. Th., Carnegie-Mellon U., Pittsburgh, Pa., May 1967.
[6]
Katz, S.M. and Manna, Z. A closer look at termination. Acta Inform. 5, 4 (1975), 333-352.
[7]
Knuth, D.E. and Bendix, P.B. Simple word problems in universal algebras. In Computational Problems in Universal Algebras, J. Leech, Ed., Pergamon Press, Oxford, 1969, pp. 263-297,
[8]
Lankford, D.S. Canonical algebraic simplification in computational logic. Memo ATP-25, Automatic Theorem Proving Project, U. of Texas, Austin, Texas, May 1975.
[9]
Lipton, R.J. and Snyder, L. On the halting of tree replacement systems. Proc. Conf. on Theoret. Comptr. Sci., Waterloo, Ontario, Aug. 1977, pp. 43-46.
[10]
Manna, Z. and Ness, S. On the termination of Markov algorithms. Proc. Third Hawaii Int. Conf. on Syst. Sci., Honolulu, Hawaii, Jan. 1970, pp. 789-792.
[11]
Manna, Z. and Waldinger, R.J. Is SOMETIME sometimes better than ALWAYS? Intermittent assertions in proving program correctness. Comm. ACM 21, 2 (Feb. 1978), 159-172.
[12]
Plaisted, D. Well-founded orderings for proving the termination of rewrite rules. Memo R-78-932, Dept. of Comptr. Sci., U. of Illinois, Urbana, IlL, July 1978.
[13]
Plaisted, D. A recursively defined ordering for proving termination of term rewriting systems. Memo R-78-943, Dept. of Comptr. Sci., U. of Illinois, Urbana, I11., Oct. 1978.

Cited By

View all
  1. Proving termination with multiset orderings

    Recommendations

    Comments

    Information & Contributors

    Information

    Published In

    cover image Communications of the ACM
    Communications of the ACM  Volume 22, Issue 8
    Aug. 1979
    40 pages
    ISSN:0001-0782
    EISSN:1557-7317
    DOI:10.1145/359138
    Issue’s Table of Contents
    Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, or republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from [email protected]

    Publisher

    Association for Computing Machinery

    New York, NY, United States

    Publication History

    Published: 01 August 1979
    Published in CACM Volume 22, Issue 8

    Permissions

    Request permissions for this article.

    Check for updates

    Author Tags

    1. bags
    2. multisets
    3. production systems
    4. program correctness
    5. program termination
    6. program verification
    7. reduction rules
    8. term rewriting systems
    9. tree replacement systems
    10. well-founded orderings
    11. well-founded sets

    Qualifiers

    • Article

    Contributors

    Other Metrics

    Bibliometrics & Citations

    Bibliometrics

    Article Metrics

    • Downloads (Last 12 months)216
    • Downloads (Last 6 weeks)27
    Reflects downloads up to 07 Nov 2024

    Other Metrics

    Citations

    Cited By

    View all

    View Options

    View options

    PDF

    View or Download as a PDF file.

    PDF

    eReader

    View online with eReader.

    eReader

    Get Access

    Login options

    Full Access

    Media

    Figures

    Other

    Tables

    Share

    Share

    Share this Publication link

    Share on social media