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Homomorphisms on Graph-Walking Automata

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Implementation and Application of Automata (CIAA 2022)

Abstract

Graph-walking automata (GWA) analyze an input graph by moving between its nodes, following the edges. This paper investigates the effect of node-replacement graph homomorphisms on recognizability by these automata. The family of graph languages recognized by GWA is closed under inverse homomorphisms. The main result of this paper is that, for n-state automata operating on graphs with k labels of edge end-points, the inverse homomorphic images require GWA with \(kn+O(1)\) states in the worst case. The second result is that already for tree-walking automata, the family they recognize is not closed under injective homomorphisms; here the proof is based on a homomorphic characterization of regular tree languages.

This work was supported by the Ministry of Science and Higher Education of the Russian Federation, agreement 075-15-2019-1619.

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References

  1. Bojanczyk, M., Colcombet, T.: Tree-walking automata cannot be determinized. Theor. Comput. Sci. 350(2–3), 164–173 (2006)

    Article  MathSciNet  Google Scholar 

  2. Bojanczyk, M., Colcombet, T.: Tree-walking automata do not recognize all regular languages. SIAM J. Comput. 38(2), 658–701 (2008)

    Article  MathSciNet  Google Scholar 

  3. Budach, L.: Automata and labyrinths. Mathematische Nachrichten 86(1), 195–282 (1978)

    Article  MathSciNet  Google Scholar 

  4. Culík, K., II., Fich, F.E., Salomaa, A.: A homomorphic characterization of regular languages. Discret. Appl. Math. 4(2), 149–152 (1982)

    Article  MathSciNet  Google Scholar 

  5. Disser, Y., Hackfeld, J., Klimm, M.: Tight bounds for undirected graph exploration with pebbles and multiple agents. J. ACM 66(6), 40:1–40:41 (2019)

    Google Scholar 

  6. Fraigniaud, P., Ilcinkas, D., Peer, G., Pelc, A., Peleg, D.: Graph exploration by a finite automaton. Theor. Comput. Sci. 345(2–3), 331–344 (2005)

    Article  MathSciNet  Google Scholar 

  7. Geffert, V., Mereghetti, C., Pighizzini, G.: Converting two-way nondeterministic unary automata into simpler automata. Theor. Comput. Sci. 295, 189–203 (2003)

    Article  MathSciNet  Google Scholar 

  8. Geffert, V., Okhotin, A.: Deterministic one-way simulation of two-way deterministic finite automata over small alphabets. In: Han, Y., Ko, S. (eds.) Descriptional Complexity of Formal Systems - 23rd IFIP WG 1.02 International Conference, DCFS 2021, Virtual Event, 5 September 2021, Proceedings. LNCS, vol. 13037, pp. 26–37. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-93489-7_3

  9. Jirásková, G., Okhotin, A.: On the state complexity of operations on two-way finite automata. Inf. Comput. 253, 36–63 (2017)

    Article  MathSciNet  Google Scholar 

  10. Kapoutsis, C.: Removing bidirectionality from nondeterministic finite automata. In: Jedrzejowicz, J., Szepietowski, A. (eds.) MFCS 2005. LNCS, vol. 3618, pp. 544–555. Springer, Heidelberg (2005). https://doi.org/10.1007/11549345_47

    Chapter  Google Scholar 

  11. Kapoutsis, C.A., Pighizzini, G.: Two-way automata characterizations of l/poly versus NL. Theory Comput. Syst. 56(4), 662–685 (2015)

    Article  MathSciNet  Google Scholar 

  12. Kunc, M., Okhotin, A.: Describing periodicity in two-way deterministic finite automata using transformation semigroups. In: Mauri, G., Leporati, A. (eds.) DLT 2011. LNCS, vol. 6795, pp. 324–336. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-22321-1_28

    Chapter  MATH  Google Scholar 

  13. Kunc, M., Okhotin, A.: State complexity of operations on two-way finite automata over a unary alphabet. Theor. Comput. Sci. 449, 106–118 (2012)

    Article  MathSciNet  Google Scholar 

  14. Kunc, M., Okhotin, A.: Reversibility of computations in graph-walking automata. Inf. Comput. 275, 104631 (2020)

    Article  MathSciNet  Google Scholar 

  15. Latteux, M., Leguy, J.: On the composition of morphisms and inverse morphisms. In: Diaz, J. (ed.) ICALP 1983. LNCS, vol. 154, pp. 420–432. Springer, Heidelberg (1983). https://doi.org/10.1007/BFb0036926

    Chapter  MATH  Google Scholar 

  16. Martynova, O., Okhotin, A.: Lower bounds for graph-walking automata. In: Bläser, M., Monmege, B. (eds.) 38th International Symposium on Theoretical Aspects of Computer Science, STACS 2021, 16–1, March 2021, Saarbrücken, Germany (Virtual Conference). LIPIcs, vol. 187, pp. 52:1–52:13. Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)

    Google Scholar 

  17. Martynova, O., Okhotin, A.: State complexity of union and intersection on graph-walking automata. In: Han, Y., Ko, S. (eds.) Descriptional Complexity of Formal Systems - 23rd IFIP WG 1.02 International Conference, DCFS 2021, Virtual Event, September 5, 2021, Proceedings. LNCS, vol. 13037, pp. 125–136. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-93489-7_11

  18. Petrov, S., Okhotin, A.: On the transformation of two-way deterministic finite automata to unambiguous finite automata. In: Leporati, A., Martín-Vide, C., Shapira, D., Zandron, C. (eds.) LATA 2021. LNCS, vol. 12638, pp. 81–93. Springer, Cham (2021). https://doi.org/10.1007/978-3-030-68195-1_7

    Chapter  MATH  Google Scholar 

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Correspondence to Alexander Okhotin .

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Martynova, O., Okhotin, A. (2022). Homomorphisms on Graph-Walking Automata. In: Caron, P., Mignot, L. (eds) Implementation and Application of Automata. CIAA 2022. Lecture Notes in Computer Science, vol 13266. Springer, Cham. https://doi.org/10.1007/978-3-031-07469-1_14

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  • DOI: https://doi.org/10.1007/978-3-031-07469-1_14

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