Abstract
We show how some problems in additive number theory can be attacked in a novel way, using techniques from the theory of finite automata. We start by recalling the relationship between first-order logic and finite automata, and use this relationship to solve several problems involving sums of numbers defined by their base-2 and Fibonacci representations. Next, we turn to harder results. Recently, Cilleruelo, Luca, & Baxter proved, for all bases b ≥ 5, that every natural number is the sum of at most 3 natural numbers whose base-b representation is a palindrome (Cilleruelo et al., Math. Comput. 87, 3023–3055, 2018). However, the cases b = 2, 3, 4 were left unresolved. We prove that every natural number is the sum of at most 4 natural numbers whose base-2 representation is a palindrome. Here the constant 4 is optimal. We obtain similar results for bases 3 and 4, thus completely resolving the problem of palindromes as an additive basis. We consider some other variations on this problem, and prove similar results. We argue that heavily case-based proofs are a good signal that a decision procedure may help to automate the proof.
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Allouche, J.-P., Rampersad, N., Shallit, J.: Periodicity, repetitions, and orbits of an automatic sequence. Theoret. Comput. Sci. 410, 2795–2803 (2009)
Aloui, K., Mauduit, C., Mkaouar, M.: Somme des chiffres et répartition dans les classes de congruence pour les palindromes ellipséphiques. Acta Math. Hung. 151, 409–455 (2017)
Alur, R., Madhusudan, P.: Visibly Pushdown Languages. In: Proc. Thirty-Sixth Ann. ACM Symp. Theor. Comput. (STOC), pp. 202–211, ACM (2004)
Alur, R., Madhusudan, P.: Adding nested structure to words. J. Assoc. Comput. Mach. 56 (2009), Art. 16
Appel, K., Haken, W.: Every planar map is four colorable. I. Discharging Illinois J. Math. 21, 429–490 (1977)
Appel, K., Haken, W., Koch, J.: Every planar map is four colorable. II. Reducibility Illinois J. Math. 21, 491–567 (1977)
Ashbacher, C.: More on palindromic squares. J. Recreat. Math. 22, 133–135 (1990)
Banks, W.D.: Every natural number is the sum of forty-nine palindromes. INTEGERS — Electronic J. Combinat. Number Theory 16 (2016), #A3 (electronic)
Banks, W.D., Hart, D.N., Sakata, M.: Almost all palindromes are composite. Math. Res. Lett. 11, 853–868 (2004)
Banks, W.D., Shparlinski, I.E.: Prime divisors of palindromes. Period. Math Hung. 51, 1–10 (2005)
Banks, W.D., Shparlinski, I.E.: Average value of the Euler function on binary palindromes. Bull. Pol. Acad. Sci Math. 54, 95–101 (2006)
Barnett, J.K.R.: Tables of square palindromes in bases 2 and 10. J. Recreat. Math. 23(1), 13–18 (1991)
Basić, B. : On d-digit palindromes in different bases: the number of bases is unbounded. Internat. J. Number Theory 8, 1387–1390 (2012)
Basić, B.: On “very palindromic” sequences. J. Korean Math. Soc. 52, 765–780 (2015)
Bell, J., Hare, K., Shallit, J.: When is an automatic set an additive basis. Proc. Amer. Math. Soc. Ser. B 5, 50–63 (2018)
Bell, J.P., Lidbetter, T.F., Shallit, J.: Additive number theory via approximation by regular languages. In: Hoshi, M., Seki, S. (eds.) DLT Vol. 11088 of Lecture Notes in Computer Science, pp 121–132. Springer, Berlin (2018)
Bérczes, A., Ziegler, V.: On simultaneous palindromes. J. Combin. Number Theory 6, 37–49 (2014)
Berlekamp, E.R., Conway, J.H., Guy, R.K.: Winning Ways for your Mathematical Plays, Vol. 2 Games in Particular. Academic Press, Cambridge (1982)
Berstel, J.: Axel Thue’s Papers on Repetitions in Words: a Translation. Number 20 in Publications Du Laboratoire De Combinatoire Et d’Informatique Mathématique. Université du Québec à Montréal (1995)
von Braunmühl, B., Verbeek, R.: Input-driven languages are recognized in n space. In: Karpinski, M. (ed.) Foundations of Computation Theory, FCT 83, Vol. 158 of Lecture Notes in Computer Science, pp 40–51. Springer, Berlin (1983)
Bruyère, V., Hansel, G.: Bertrand numeration systems and recognizability. Theoret. Comput. Sci. 181, 17–43 (1997)
Bruyère, V., Hansel, G., Michaux, C., Villemaire, R.: Logic and p-recognizable sets of integers. Bull. Belgian Math. Soc. 1, 191–238 (1994). Corrigendum, Bull. Belg. Math. Soc. 1 (1994) 577
Büchi, J.R.: Weak secord-order arithmetic and finite automata. Zeitschrift fur̈ mathematische Logik und Grundlagen der Mathematik 6, 66–92 (1960). Reprinted in S. Mac Lane and D. Siefkes, eds., The Collected Works of J. Richard Buchï, Springer, 1990, pp.398–424
Charlier, E., Rampersad, N., Shallit, J.: Enumeration and decidable properties of automatic sequences. Internat. J. Found. Comp. Sci. 23, 1035–1066 (2012)
Cilleruelo, J., Luca, F.: Every positive integer is a sum of three palindromes. arXiv:1602.06208v1 (2016)
Cilleruelo, J., Luca, F., Baxter, L.: Every positive integer is a sum of three palindromes. Math. Comput. 87, 3023–3055 (2018)
Cilleruelo, J., Luca, F., Shparlinski, I.E.: Power values of palindromes. J Combin. Number Theory 1, 101–107 (2009)
Cilleruelo, J., Tesoro, R., Luca, F.: Palindromes in linear recurrence sequences. Monatsh. Math. 171, 433–442 (2013)
Col, S.: Palindromes dans les progressions arithmétiques. Acta Arith. 137, 1–41 (2009)
Du, C.F., Mousavi, H., Rowland, E., Schaeffer, L.: J. Shallit. Decision algorithms for Fibonacci-automatic words II: related sequences and avoidability. Theoret. Comput. Sci. 657, 146–162 (2017)
Du, C.F., Mousavi, H., Schaeffer, L., Shallit, J.: Decision algorithms for Fibonacci-automatic words III: enumeration and abelian properties. Internat. J. Found. Comp. Sci. 27, 943–963 (2016)
Dymond, P.W.: Input-driven languages are in n depth. Inform. Process. Lett. 26, 247–250 (1988)
Goč, D., Henshall, D., Shallit, J.: Automatic theorem-proving in combinatorics on words. In: Moreira, N., Reis, R. (eds.) CIAA 2012, Vol. 7381 of Lecture Notes in Computer Science, pp 180–191. Springer, Berlin (2012)
Goč, D., Mousavi, H., Shallit, J.: On the number of unbordered factors. In: Dediu, A.-H., Martin-Vide, C., Truthe, B. (eds.) LATA 2013, Vol. 7810 of Lecture Notes in Computer Science, pp 299–310. Springer, Berlin (2013)
Goč, D., Saari, K., Shallit, J.: Primitive words and Lyndon words in automatic and linearly recurrent sequences. In: Dediu, A.-H., Martin-Vide, C., Truthe, B. (eds.) LATA 2013, Primitive Vol. 7810 of Lecture Notes in Computer Science, pp 311–322. Springers, Berlin (2013)
Goč, D., Schaeffer, L., Shallit, J.: The subword complexity of k-automatic sequences is k-synchronized. In: Béal, M.-P., Carton, O. (eds.) DLT 2013, Vol. 7907 of Lecture Notes in Computer Science, pp 252–263. Springer, Berlin (2013)
Goins, E.H.: Palindromes in different bases: a conjecture of J. Ernest Wilkins. INTEGERS — Electronic J. Combinat. Number Theory 9, 725–734 (2009). Paper #A55, (electronic)
Han, Y.-S., Salomaa, K.: Nondeterministic state complexity of nested word automata. Theoret. Comput. Sci. 410, 2961–2971 (2009)
Haque, S., Shallit, J.: Discriminators and k-regular sequences. INTEGERS — Electronic J. Combinat. Number Theory 16, A76 (2016). (electronic)
Hardy, G.H., Wright, E.M.: An Introduction to the Theory of Numbers, 5th edn. Oxford University Press, Oxford (1985)
Harminc, M., Soták, R.: Palindromic numbers in arithmetic progressions. Fibonacci Quart. 36, 259–262 (1998)
Heizmann, M., Hoenicke, J., Podelski, A.: Software model checking for people who love automata. In: Sharygina, N., Veith, H. (eds.) Computer Aided Verification — 25th International Conference, CAV 2013, vol. 8044 of Lecture Notes in Computer Science, pp 36–52. Springer, Berlin (2013)
Heizmann, M., Dietsch, D., Greitschus, M., Leike, J., Musa, B., Schätzle, C., Podelski, A.: Ultimate automizer with two-track proofs. In: Chechik, M., Raskin, J.-F. (eds.) Tools and Algorithms for the Construction and Analysis of Systems — 22nd International Conference, TACAS 2016, vol. 9636 of Lecture Notes in Computer Science, pp 950–953. Springer, Berlin (2016)
Hernández, S., Luca, F.: Palindromic powers. Rev. Colombiana Mat. 40, 81–86 (2006)
Hopcroft, J.E., Ullman, J.D.: Introduction to Automata Theory, Languages, and Computation. Addison-Wesley, Boston (1979)
Kane, D.M., Sanna, C., Shallit, J.: Waring’s Theorem for Binary Powers. arXiv:1801.04483. To appear, Combinatorica (2018)
Keith, M.: Classification and enumeration of palindromic squares. J. Recreat. Math. 22(2), 124–132 (1990)
Kidder, P., Kwong, H.: Remarks on integer palindromes. J. Recreat. Math. 36, 299–306 (2007)
Korec, I.: Palindromic squares for various number system bases. Math. Slovaca 41, 261–276 (1991)
Kresová, H., Sǎlát, T.: On palindromic numbers. Acta Math. Univ Comenian. 42(/43), 293–298 (1984)
La Torre, S., Napoli, M., Parente, M.: On the membership problem for visibly pushdown languages. In: Graf, S., Zhang, W. (eds.) ATVA 2006, vol. 4218 of Lecture Notes in Computer Science, pp. 96–109, Springer (2006)
Lekkerkerker, C.G.: Voorstelling van natuurlijke getallen door een som van getallen van Fibonacci. Simon Stevin 29, 190–195 (1952)
Luca, F.: Palindromes in Lucas sequences. Monatsh. Math. 138, 209–223 (2003)
Luca, F., Togbé, A.: On binary palindromes of the form 10n1. C. R. Acad. Sci. Paris 346, 487–489 (2008)
Luca, F., Young, P.T.: On the Binary Expansion of the Odd Catalan Numbers. In: Proc. 14Th Int. Conf. on Fibonacci Numbers and Their Applications, pp. 185–190. Soc. Mat. Mexicana (2011)
Madhusudan, P., Nowotka, D., Rajasekaran, A., Shallit, J.: Lagrange’s theorem for binary squares. In: Potapov, I., Spirakis, P., Worrell, J. (eds.) 43rd International Symposium on Mathematical Foundations of Computer Science (MFCS 2018), Leibniz International Proceedings in Informatics, pp. 18:1–18:14. Schloss Dagstuhl—Leibniz-Zentrum für Informatik, Germany (2018)
McCune, W.: Solution of the Robbins problem. J. Autom. Reason. 19(3), 263–276 (1997)
Mehlhorn, K.: Pebbling Mountain Ranges and Its Application of DCFL-Recognition. In: Proc. 7Th Int’l Conf. on Automata, Languages, and Programming (ICALP), Vol. 85 of Lecture Notes in Computer Science, pp. 422–435. Springer (1980)
Mousavi, H.: Automatic theorem proving in Walnut. arXiv:1603.06017 (2016)
Mousavi, H., Schaeffer, L., Shallit, J.: Decision algorithms for Fibonacci-automatic words, I Basic results. RAIRO Inform. Théor. App. 50, 39–66 (2016)
Nathanson, M.B.: Additive Number Theory: The Classical Bases. Springer, Berlin (1996)
Ogden, W.: A helpful result for proving inherent ambiguity. Math. Systems Theory 2, 191–194 (1968)
Okhotin, A., Salomaa, K.: State complexity of operations on input-driven pushdown automata. J Comput. System Sci. 86, 207–228 (2017)
Piao, X., Salomaa, K.: Operational state complexity of nested word automata. Theoret. Comput. Sci. 410, 3290–3302 (2009)
Pollack, P.: Palindromic sums of proper divisors. INTEGERS — Electronic J. Combinat. Number Theory 15A, Paper #A13 (electronic) (2015)
Rajasekaran, A.: Using automata theory to solve problems in additive number theory. Master’s thesis, School of Computer Science, University of Waterloo, 2018. Available at https://uwspace.uwaterloo.ca/handle/10012/13202
Rajasekaran, A., Smith, T., Shallit, J.: Sums of palindromes: an approach via automata. In: Niedermeier, R., Vallée, B. (eds.) 35th Symposium on Theoretical Aspects of Computer Science (STACS 2018), Leibniz International Proceedings in Informatics, pp. 54:1–54:12. Schloss Dagstuhl — Leibniz-Zentrum fur̈ Informatik (2018)
Salomaa, K.: Limitations of lower bound methods for deterministic nested word automata. Inform. Comput. 209, 580–589 (2011)
Shallit, J.: Decidability and enumeration for automatic sequences: a survey. In: Bulatov, A.A., Shur, A.M. (eds.) CSR 2013, vol. 7913 of Lecture Notes in Computer Science, pp 49–63. Springer, Berlin (2013)
Shorey, T.N.: On the equation zq = (xn − 1)/(x − 1). Indag. Math. 48, 345–351 (1986)
Sigg, M.: On a conjecture of John Hoffman regarding sums of palindromic numbers. arXiv:1510.07507 (2015)
Simmons, G.J.: On palindromic squares of non-palindromic numbers. J. Recreat. Math. 5(1), 11–19 (1972)
Sloane, N.J.A., et al.: The on-line encyclopedia of integer sequences Available at https://oeis.org (2019)
Thue, A.: ÜBer die gegenseitige Lage gleicher Teile gewisser Zeichenreihen. Norske vid. Selsk. Skr. Mat. Nat. Kl. 1, 1–67 (1912). Reprinted in Selected Mathematical Papers of Axel Thue, T. Nagell, editor, Universitetsforlaget, Oslo, 1977, 413–478
Trigg, C.: Infinite sequences of palindromic triangular numbers. Fibonacci Quart. 12, 209–212 (1974)
Tymoczko, T.: The four-color problem and its philosophical significance. J. Philosophy 76(2), 57–83 (1979)
Vaughan, R.C., Wooley, T.: Number Theory for the Millennium. III, pp. 301–340. A. K. Peters. In: Bennett, M.A., Berndt, B.C., Boston, N., Diamond, H.G., Hildebrand, A.J., Philipp, W. (eds.) (2002)
Yates, S.: The mystique of repunits. Math. Mag. 51, 22–28 (1978)
Zeckendorf, E.: Représentation des nombres naturels par une somme de nombres de Fibonacci ou de nombres de Lucas. Bull. Soc. Roy. Liége 41, 179–182 (1972)
Acknowledgments
We thank Dirk Nowotka, Parthasarathy Madhusudan, and Jean-Paul Allouche for helpful discussions. We thank the creators of the ULTIMATE automaton library for their assistance. We are also grateful to the referees for reading our paper with care and making several helpful suggestions.
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Rajasekaran, A., Shallit, J. & Smith, T. Additive Number Theory via Automata Theory. Theory Comput Syst 64, 542–567 (2020). https://doi.org/10.1007/s00224-019-09929-9
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DOI: https://doi.org/10.1007/s00224-019-09929-9