Abstract

In this paper we extend the work of Campeanu, Salomaa and Yu [1] on extended regular expressions featured in the Unix utility egrep and the popular scripting language Perl. We settle the open issue of closure under intersection and provide an improved pumping lemma that will show that a larger class of languages is not recognizable by extended regular expressions. We also investigate some questions regarding extended multi-pattern languages introduced by Nagy in [2].

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Câmpeanu, C., Salomaa, K., Yu, S.: A formal study of practical regular expressions. Int. J. Found. Comput. Sci. 14, 1007–1018 (2003)MathSciNetCrossRefMATHGoogle Scholar
  2. 2.
    Nagy, B.: On the language equivalence of NE star-patterns. Inf. Process. Lett. 95, 396–400 (2005)MathSciNetCrossRefMATHGoogle Scholar
  3. 3.
    Kari, L., Mateescu, A., Paun, G., Salomaa, A.: Multi-pattern languages. Theor. Comput. Sci. 141, 253–268 (1995)MathSciNetCrossRefMATHGoogle Scholar
  4. 4.
    Aho, A.V.: Algorithms for finding patterns in strings. In: Handbook of Theoretical Computer Science. Algorithms and Complexity (A), vol. A, pp. 255–300. MIT Press, Cambridge (1990)Google Scholar
  5. 5.
    Gallier, J.H.: Logic for Computer Science: Foundations of Automatic Theorem Proving. Harper & Row (1986)Google Scholar
  6. 6.
    Dumitrescu, S., Păun, G., Salomaa, A.: Languages associated to finite and infinite patterns. Rev. Roum. Math. Pures Appl. 41, 607–625 (1996)MathSciNetGoogle Scholar
  7. 7.
    Bertsch, E., Nederhof, M.J.: Regular closure of deterministic languages. SIAM J. Comput. 29, 81–102 (1999)MathSciNetCrossRefMATHGoogle Scholar
  8. 8.
    Kutrib, M., Malcher, A.: Finite turns and the regular closure of linear context-free languages. Discrete Applied Mathematics 155, 2152–2164 (2007)MathSciNetCrossRefMATHGoogle Scholar
  9. 9.
    Jiang, T., Salomaa, A., Salomaa, K., Yu, S.: Decision problems for patterns. J. Comput. Syst. Sci. 50, 53–63 (1995)MathSciNetCrossRefMATHGoogle Scholar
  10. 10.
    Nagy, B.: A normal form for regular expressions. In: Eighth International Conference on Developments in Language Theory (DLT 2004), Auckland, New Zealand (2004), www.cs.auckland.ac.nz/CDMTCS/researchreports/252dlt04.pdf
  11. 11.
    Carle, B., Narendran, P., Scheriff, C.: On extended regular expressions. In: Twenty-first International Workshop on Unification (UNIF 2007), Paris, France (June 2007)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  • Benjamin Carle
    • 1
  • Paliath Narendran
    • 1
  1. 1.Dept. of Computer ScienceUniversity at Albany–SUNYAlbanyUSA

Personalised recommendations