Skip to main content
Log in

On the Enumeration of Hypermaps Which are Self-Equivalent with Respect to Reversing the Colors of Vertices

  • Published:
Journal of Mathematical Sciences Aims and scope Submit manuscript

A map (S,G) is a closed Riemann surface S with embedded graph G such that S \G is the disjoint union of connected components, called faces, each of which is homeomorphic to an open disk. Tutte began a systematic study of maps in the 1960s and contemporary authors are actively developing it. In the present paper, after recalling the concept of a circular map introduced by the author and Mednykh, a relationship between bipartite maps and circular maps is demonstrated via the concept of the duality of maps. In this way an enumeration formula for the number of bipartite maps with a given number of edges is obtained. A hypermap is a map whose vertices are colored black and white in such a way that every edge connects vertices of different colors. The hypermaps are also known as dessins d’enfants (or Grothendieck’s dessins).

A hypermap is self-equivalent with respect to reversing the colors of vertices if it is equivalent to the hypermap obtained by reversing the colors of its vertices.

The main result of the present paper is an enumeration formula for the number of unrooted hypermaps, regardless of genus, which have n edges and are self-equivalent with respect to reversing the colors of vertices. Bibliography: 13 titles.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

References

  1. R. Cori, “Un code pour les graphes planaires et ses applications,” Thèse de Doctorat, Paris (1973).

  2. M. A. Deryagina and A. D. Mednykh, “On the enumeration of circular maps with given number of edges,” Sib. Mat. Zh., 54, No. 4, 624–639 (2013).

    Article  MathSciNet  MATH  Google Scholar 

  3. A. Grothendieck, “Esquisse d’un programme,” in: Geometric Galois Action, Cambridge Univ. Press (1997), pp. 5–48.

  4. M. Hall Jr., “Subgroups of finite index in free groups,” Canad. J. Math., 1, 187–190 (1949).

    Article  MathSciNet  MATH  Google Scholar 

  5. D. M. Jackson and T. I. Visentin, An Atlas of the Smaller Maps in Orientable and Nonorientable Surfaces, Chapman and Hall, Boca Raton (2001).

    MATH  Google Scholar 

  6. S. K. Lando and A. K. Zvonkin, Graphs on Surfaces and Their Applications, Springer-Verlag (2004).

  7. V. A. Liskovets, “On the enumeration of subgroups of a free group,” Dokl. Akad. Nauk BSSR, 15, No. 1, 6–9 (1971).

    MathSciNet  Google Scholar 

  8. V. A. Liskovets, “Enumerative formulae for unrooted planar maps: a pattern,” Electron. J. Combin., 11, R88 (2004).

    MathSciNet  MATH  Google Scholar 

  9. V. A. Liskovets and T. R. S Walsh, “Enumeration of Eulerian and unicursal planar maps,” Discr. Math., 282, 209–221 (2004).

  10. A. Mednykh and R. Nedela, “Enumeration of unrooted hypermaps of a given genus,” Discr. Math., 310, No. 3, 518–526 (2010).

    Article  MathSciNet  MATH  Google Scholar 

  11. N. J. A. Sloane, The On-Line Encyclopedia of Integer Sequences (OEIS), http://www.oeis.org.

  12. W. T. Tutte, “A census of planar maps,” Canad. J. Math., 15, 249–271 (1963).

    Article  MathSciNet  MATH  Google Scholar 

  13. T. R. S. Walsh, “Hypermaps versus bipartite maps,” J. Combin. Theory, Ser.B, 18, No. 2, 155–163 (1975).

    Article  MathSciNet  MATH  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to M. Deryagina.

Additional information

Published in Zapiski Nauchnykh Seminarov POMI, Vol. 446, 2016, pp. 31–39.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Deryagina, M. On the Enumeration of Hypermaps Which are Self-Equivalent with Respect to Reversing the Colors of Vertices. J Math Sci 226, 561–567 (2017). https://doi.org/10.1007/s10958-017-3550-x

Download citation

  • Received:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10958-017-3550-x

Navigation