Abstract
The piecewise complexity h(u) of a word is the minimal length of subwords needed to exactly characterise u. Its piecewise minimality index \(\rho (u)\) is the smallest length k such that u is minimal among its order-k class \([u]_k\) in Simon’s congruence.
We study these two measures and provide efficient algorithms for computing h(u) and \(\rho (u)\). We also provide efficient algorithms for the case where u is a periodic word, of the form \(u=v^n\).
Work supported by IRL ReLaX. J. Veron supported by DIGICOSME ANR-11-LABX-0045.
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Notes
- 1.
In fact \(\delta (u,v)\) is a measure of similarity and not of difference, between u and v. The associated distance is actually \(d(u,v){\mathop {=}\limits ^{\text{ def }}}2^{-\delta (u,v)}\) [SS83].
References
Barker, L., Fleischmann, P., Harwardt, K., Manea, F., Nowotka, D.: Scattered factor-universality of words. In: Jonoska, N., Savchuk, D. (eds.) DLT 2020. LNCS, vol. 12086, pp. 14–28. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-48516-0_2
Bojańczyk, M., Segoufin, L., Straubing, H.: Piecewise testable tree languages. Logical Methods Comput. Sci. 8(3), 1–32 (2012)
Carton, O., Pouzet, M.: Simon’s theorem for scattered words. In: Hoshi, M., Seki, S. (eds.) DLT 2018. LNCS, vol. 11088, pp. 182–193. Springer, Cham (2018). https://doi.org/10.1007/978-3-319-98654-8_15
Diekert, V., Gastin, P., Kufleitner, M.: A survey on small fragments of first-order logic over finite words. Int. J. Found. Comput. Sci. 19(3), 513–548 (2008)
Fleischer, L., Kufleitner, M.: Testing Simon’s congruence. In: Proceedings of MFCS 2018, vol. 117 of Leibniz International Proceedings in Informatics, pp. 62:1–62:13. Leibniz-Zentrum für Informatik (2018)
Gawrychowski, P., Kosche, M., Koß, T., Manea, F., Siemer, S.: Efficiently testing Simon’s congruence. In: Proceedings of STACS 2021, vol. 187 of Leibniz International Proceedings in Informatics, pp. 34:1–34:18. Leibniz-Zentrum für Informatik (2021)
Goubault-Larrecq, J., Schmitz, S.: Deciding piecewise testable separability for regular tree languages. In: Proceedings of ICALP 2016, vol. 55 of Leibniz International Proceedings in Informatics, pp. 97:1–97:15. Leibniz-Zentrum für Informatik (2016)
Hébrard, J.-J.: An algorithm for distinguishing efficiently bit-strings by their subsequences. Theor. Comput. Sci. 82(1), 35–49 (1991)
Halfon, S., Schnoebelen, Ph.: On shuffle products, acyclic automata and piecewise-testable languages. Inf. Process. Lett. 145, 68–73 (2019)
Kontorovich, L., Cortes, C., Mohri, M.: Kernel methods for learning languages. Theor. Comput. Sci. 405(3), 223–236 (2008)
Karandikar, P., Kufleitner, M., Schnoebelen, Ph.: On the index of Simon’s congruence for piecewise testability. Inf. Process. Lett. 115(4), 515–519 (2015)
Klíma, O.: Piecewise testable languages via combinatorics on words. Disc. Math. 311(20), 2124–2127 (2011)
Karandikar, P., Schnoebelen, Ph.: The height of piecewise-testable languages with applications in logical complexity. In Proceedings of CSL 2016, vol. 62 of Leibniz International Proceedings in Informatics, pp. 37:1–37:22. Leibniz-Zentrum für Informatik (2016)
Karandikar, P., Schnoebelen, Ph.: The height of piecewise-testable languages and the complexity of the logic of subwords. Logical Methods Comput. Sci. 15(2) (2019)
Matz, O.: On piecewise testable, starfree, and recognizable picture languages. In: Nivat, M. (ed.) FoSSaCS 1998. LNCS, vol. 1378, pp. 203–210. Springer, Heidelberg (1998). https://doi.org/10.1007/BFb0053551
Masopust, T., Thomazo, M.: On the complexity of k-piecewise testability and the depth of automata. In: Potapov, I. (ed.) DLT 2015. LNCS, vol. 9168, pp. 364–376. Springer, Cham (2015). https://doi.org/10.1007/978-3-319-21500-6_29
Pin, J.É.: Varieties of Formal Languages. Plenum, New-York (1986)
Perrin, D., Pin, J.-É.: Infinite words: Automata, Semigroups, Logic and Games, vol. 141 of Pure and Applied Mathematics Series. Elsevier (2004)
Rogers, J., Heinz, J., Fero, M., Hurst, J., Lambert, D., Wibel, S.: Cognitive and sub-regular complexity. In: Morrill, G., Nederhof, M.-J. (eds.) FG 2012-2013. LNCS, vol. 8036, pp. 90–108. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-39998-5_6
Simon, I.: Hierarchies of Event with Dot-Depth One. PhD thesis, University of Waterloo, Waterloo, ON, Canada (1972)
Simon, I.: Piecewise testable events. In: Brakhage, H. (ed.) GI-Fachtagung 1975. LNCS, vol. 33, pp. 214–222. Springer, Heidelberg (1975). https://doi.org/10.1007/3-540-07407-4_23
Simon, I.: Words distinguished by their subwords. In: Proceedings of WORDS 2003 (2003)
Sakarovitch, J., Simon, I.: Subwords. In: Lothaire, M. (ed.) Combinatorics on Words, vol. 17 of Encyclopedia of Mathematics and Its Applications, chap. 6, pp. 105–142. Cambridge University Press (1983)
Schnoebelen, Ph., Veron, J.: On arch factorization and subword universality for words and compressed words. In: Proceedings of WORDS 20123, vol. 13899 of Lecture Notes in Computer Science, pp. 274–287. Springer, Heidelberg (2023). https://doi.org/10.1007/978-3-031-33180-0_21
Zetzsche, G.: Separability by piecewise testable languages and downward closures beyond subwords. In: Proceedings of LICS 2018, pp. 929–938. ACM Press (2018)
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Praveen, M., Schnoebelen, P., Veron, J., Vialard, I. (2024). On the Piecewise Complexity of Words and Periodic Words. In: Fernau, H., Gaspers, S., Klasing, R. (eds) SOFSEM 2024: Theory and Practice of Computer Science. SOFSEM 2024. Lecture Notes in Computer Science, vol 14519. Springer, Cham. https://doi.org/10.1007/978-3-031-52113-3_32
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