Abstract
I present a short, mechanically checked Isabelle/HOL formalization of Higman’s lemma by open induction.
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Notes
- 1.
Dagstuhl Seminar 16031: www.dagstuhl.de/16031.
- 2.
In fact, demanding transitivity suffices, since reflexivity is immediate for almost-full relations.
References
Berger, U. (2004). A computational interpretation of open induction. In 19th IEEE symposium on logic in computer science (LICS 2004) (pp. 326–334). https://doi.org/10.1109/LICS.2004.1319627.
Berghofer, S. (2004). A constructive proof of Higman’s lemma in Isabelle. In Berardi, S., Coppo, M., & Damiani, F. (Eds.), Types for proofs and programs: international workshop, TYPES 2003, Torino, Italy, April 30–May 4, 2003, Revised selected papers (pp. 66–82). Berlin: Springer. https://doi.org/10.1007/978-3-540-24849-1_5.
Coquand, T., & Fridlender, D. (1993). A proof of Higman’s lemma by structural induction. Unpublished manuscript.
Felgenhauer, B. (2015). Decreasing Diagrams II. Archive of Formal Proofs. https://isa-afp.org/entries/Decreasing-Diagrams-II.shtml. Formal proof development.
Felgenhauer, B., & van Oostrom, V. (2013) Proof orders for decreasing diagrams. In van Raamsdonk, F. (Ed.), 24th International Conference on Rewriting Techniques and Applications (RTA 2013). Leibniz International Proceedings in Informatics (LIPIcs) (Vol. 21, pp. 174–189). Dagstuhl, Germany: Schloss Dagstuhl–Leibniz-Zentrum fuer Informatik. https://doi.org/10.4230/LIPIcs.RTA.2013.174.
Fridlender, D. (1998). Higman’s lemma in type theory. In Giménez, E., & Paulin-Mohring, C. (Eds.), Types for proofs and programs: international workshop TYPES’96 Aussois, France, December 15–19, 1996 selected papers (pp. 112–133). Berlin: Springer. https://doi.org/10.1007/BFb0097789.
Geser, A. (1996, April). A proof of Higman’s lemma by open induction. Technical Report MIP-9606, Universitt Passau.
Higman, G. (1952). Ordering by divisibility in abstract algebras. Proceedings of the London Mathematical Society, s3-2(1), 326–336. https://doi.org/10.1112/plms/s3-2.1.326.
Kruskal, J. B. (1960). Well-quasi-ordering, the Tree Theorem, and Vazsonyi’s conjecture. Transactions of the American Mathematical Society, 95(2), 210–225. https://doi.org/10.1090/S0002-9947-1960-0111704-1.
Kruskal, J. B. (1972). The theory of well-quasi-ordering: a frequently discovered concept. Journal of Combinatorial Theory, Series A, 13(3), 297–305. https://doi.org/10.1016/0097-3165(72)90063-5.
Larchey-Wendling, D. (2015). A mechanized inductive proof of Kruskal’s tree theorem.
Murthy, C., & Russell, J. R. (1989, October) A constructive proof of Higman’s lemma. Technical Report TR 89-1049, Cornell University, Ithaca, NY 14853-7501. http://hdl.handle.net/1813/6849.
Murthy, C. R., & Russell, J. R. (1990). A constructive proof of Higman’s lemma. In Proceedings of the Fifth Annual Symposium on Logic in Computer Science (LICS ’90), Philadelphia, Pennsylvania, USA, June 4–7, 1990 (pp. 257–267). https://doi.org/10.1109/LICS.1990.113752.
Nash-Williams, C. S. J. A. (1963). On well-quasi-ordering finite trees. Mathematical Proceedings of the Cambridge Philosophical Society, 59(4), 833–835. https://doi.org/10.1017/S0305004100003844.
Nipkow, T., Paulson, L. C., Wenzel, M. (2002). Isabelle/HOL-a proof assistant for higher-order logic. Lecture Notes in Computer Science (Vol. 2283). Springer. https://doi.org/10.1007/3-540-45949-9.
Ogawa, M., & Sternagel, C. (2012, November). Open induction. Archive of Formal Proofs. https://isa-afp.org/entries/Open_induction.shtml. Formal proof development.
Raoult, J.-C. (1988). Proving open properties by induction. Information Processing Letters, 29(1), 19–23. https://doi.org/10.1016/0020-0190(88)90126-3.
Richman, F., & Stolzenberg, G. (1993). Well quasi-ordered sets. Advances in Mathematics, 97(2), 145–153. https://doi.org/10.1006/aima.1993.1004.
Schwichtenberg, H., Seisenberger, M., & Wiesnet, F. (2016). Higman’s lemma and its computational content. In Kahle, R., Strahm, T., & Studer, T. (Eds.), Advances in proof theory (pp. 353–375). Cham: Springer. https://doi.org/10.1007/978-3-319-29198-7_11.
Sternagel, C. (2012, April). Well-quasi-orders. Archive of Formal Proofs. https://isa-afp.org/entries/Well_Quasi_Orders.shtml. Formal proof development.
Sternagel, C. (2014). Certified Kruskal’s tree theorem. Journal of Formalized Reasoning, 7(1), 45–62. https://doi.org/10.6092/issn.1972-5787/4213.
Sternagel, C., & Thiemann, R. (2013). Formalizing Knuth-Bendix orders and Knuth-Bendix completion. In 24th international conference on rewriting techniques and applications, Dagstuhl. LIPIcs (Vol. 21, pp. 287–302). https://doi.org/10.4230/LIPIcs.RTA.2013.287.
Thiemann, R., & Sternagel, C. (2009). Certification of termination proofs using \(\sf CeTA\). In 22nd international conference on theorem proving in higher-order logics (TPHOLs 2009). Lecture Notes in Computer Science (Vol. 5674, pp. 452–468). Springer. https://doi.org/10.1007/978-3-642-03359-9_31.
Veldman, W., & Bezem, M. (1993). Ramsey’s theorem and the pigeonhole principle in intuitionistic mathematics. Journal of the London Mathematical Society, s2-47(2), 193–211. https://doi.org/10.1112/jlms/s2-47.2.193.
Vytiniotis, D., Coquand, T., Wahlstedt, D. (2012). Stop when you are almost-full. In Beringer, L. & Felty, A. (Eds.), 3rd international conference on interactive theorem proving (ITP 2012) (pp. 250–265). Berlin: Springer. https://doi.org/10.1007/978-3-642-32347-8_17.
Wu, C., Zhang, X., Urban, C. (2011, August). The Myhill-Nerode theorem based on regular expressions. Archive of Formal Proofs. https://isa-afp.org/entries/Myhill-Nerode.shtml. Formal proof development.
Wu, C., Zhang, X., & Urban, C. (2014). A formalisation of the Myhill-Nerode theorem based on regular expressions. Journal of Automated Reasoning, 52(4), 451–480. https://doi.org/10.1007/s10817-013-9297-2.
Acknowledgements
I am grateful to Mizuhito Ogawa, who introduced me to open induction and the idea of applying it to formalize Higman’s lemma in the first place. Thanks goes also to the organizers and participants of the delightful Dagstuhl seminar on Well Quasi-Orders in Computer Science, for fruitful discussions and providing a nice atmosphere. I also want to thank Bertram Felgenhauer for giving me a nudge when I was stuck in the proof of Lemma 2(3).
Finally, I am indebted to an anonymous reviewer who pointed out many blemishes in my first draft and provided constructive (pun intended) criticism. Her or his feedback helped to improve this work and lead to a generalization (Lemma 4) of an earlier result (Corollary 2).
This work is supported by FWF (Austrian Science Fund) project P27502.
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Sternagel, C. (2020). A Mechanized Proof of Higman’s Lemma by Open Induction. In: Schuster, P., Seisenberger, M., Weiermann, A. (eds) Well-Quasi Orders in Computation, Logic, Language and Reasoning. Trends in Logic, vol 53. Springer, Cham. https://doi.org/10.1007/978-3-030-30229-0_12
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