Abstract
We analyze and reprove the famous theorem of Hmelevskii, which states that the general solutions of constant-free equations on three unknowns are finitely parameterizable, that is expressible by a finite collection of formulas of word and numerical parameters. The proof is written, and simplified, by using modern tools of combinatorics on words. As a new aspect the size of the finite representation is estimated; it is bounded by a double exponential function on the size of the equation.
Supported by the Academy of Finland under grant 8121419.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Albert, M.H., Lawrence, J.: A proof of Ehrenfeucht’s Conjecture. Theoret. Comput. Sci. 41, 121–123 (1985)
Choffrut, C., Karhumäki, J.: Combinatorics of words. In: Rozenberg, G., Salomaa, A. (eds.) Handbook of Formal Languages. Springer, Heidelberg (1997)
Czeizler, E., Karhumäki, J.: On non-periodic solutions of independent systems of word equations over three unknowns. Internat. J. Found. Comput. Sci. 18, 873–897 (2007)
Guba, V.S.: Equivalence of infinite systems of equations in free groups and semigroups to finite subsystems. Mat. Zametki 40, 321–324 (1986)
Harju, T., Karhumäki, J., Plandowski, W.: Independent system of equations. In: Lothaire, M. (ed.) Algebraic Combinatorics on Words. Cambridge University Press, Cambridge (2002)
Hmelevskii, Y.I.: Equations in free semigroups. Proc. Steklov Inst. of Math. 107 (1971); Amer. Math. Soc. Translations (1976)
Karhumäki, J., Saarela, A.: A Reproof of Hmelevskii’s Theorem (manuscript)
Lothaire, M.: Combinatorics on Words. Addison-Wesley, Reading (1983)
Makanin, G.S.: The problem of solvability of equations in a free semigroup. Mat. Sb. 103, 147–236 (1977); English transl. in Math. USSR Sb. 32, 129–198
Plandowski, W.: Satisfiability of word equations with constants is in PSPACE. J. ACM 51, 483–496 (2004)
Spehner, J.-C.: Quelques Problemes d’extension, de conjugaison et de presentation des sous-monoides d’un monoide libre. Ph.D. Thesis, Univ. Paris (1976)
Spehner, J.-C.: Les presentations des sous-monoides de rang 3 d’un monoide libre. In: Semigroups, Proc. Conf. Math. Res. Inst., pp. 116–155 (1978)
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2008 Springer-Verlag Berlin Heidelberg
About this paper
Cite this paper
Karhumäki, J., Saarela, A. (2008). An Analysis and a Reproof of Hmelevskii’s Theorem. In: Ito, M., Toyama, M. (eds) Developments in Language Theory. DLT 2008. Lecture Notes in Computer Science, vol 5257. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-85780-8_37
Download citation
DOI: https://doi.org/10.1007/978-3-540-85780-8_37
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-85779-2
Online ISBN: 978-3-540-85780-8
eBook Packages: Computer ScienceComputer Science (R0)