Enumeration of planar two-face maps

نویسندگان

  • Michel Bousquet
  • Gilbert Labelle
  • Pierre Leroux
چکیده

We enumerate unrooted planar maps (up to orientation preserving homeomorphism) having two faces, according to the number of vertices and to their vertex and face degree distributions, both in the (vertex) labelled and unlabelled cases. We rst consider plane maps, i.e., maps which are embedded in the plane, and then deduce the case of planar (or sphere) maps, embedded on the sphere. A crucial step is the enumeration of two-face plane maps having an antipodal symmetry and use is made of Liskovets' method in the process. The motivation for this research comes from the topological classiication of Belyi functions. R esum e Nous d enombrons les cartes planaires ((a hom eomorphisme pr eservant l'orientation pr es) non point ees a deux faces, selon le nombre de sommets et selon la distribution des degr es des sommets et des faces, etiquet ees (aux sommets) ou non. Nous abordons d'abord les cartes planes, c'est-a-dire plong ees dans le plan, et d eduisons ensuite le cas des cartes planaires (ou sph eriques), plong ees sur la sph ere. Une etape cruciale est le d enombrement des cartes planes a deux faces admettant une sym etrie antipodale et la m ethode de Liskovets est utilis ee pour cela. La motivation de cette recherche provient de la classiication topologique des fonctions de Belyi.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Restricted rooted non-separable planar maps

Tutte founded the theory of enumeration of planar maps in a series of papers in the 1960s. Rooted non-separable planar maps have connections, for example, to pattern-avoiding permutations, and they are in one-to-one correspondence with the β(1, 0)-trees introduced by Cori, Jacquard and Schaeffer in 1997. In this paper we enumerate 2-face-free rooted non-separable planar maps and obtain restrict...

متن کامل

Enumeration of planar 2 - face maps 1

Up to now, most of the work on maps has dealt with rooted maps, that is, maps with a distinguished and directed edge. We get rid of this restriction in the case of planar maps having two faces. We enumerate these maps according to their vertex and face degree distributions. The following classes of non rooted 2-face maps are treated: (vertex) labelled or unlabelled, embedded in the plane or on ...

متن کامل

Enumeration of self-dual planar maps

A planar map is an embedding of a connected planar graph in the sphere such that the surface is partitioned into simply connected regions; in other words, it is a finite cellular decomposition of the sphere into vertices, edges, and faces (0−, 1− and 2−cells, respectively). In particular, 3−connected planar maps correspond to polyhedra. Motivated by the Four Colour Problem, W. Tutte [4] launche...

متن کامل

Planar Maps as Labeled Mobiles

We extend Schaeffer’s bijection between rooted quadrangulations and well-labeled trees to the general case of Eulerian planar maps with prescribed face valences, in bijection with a new class of labeled trees, which we call mobiles. Our bijection covers all the classes of maps previously enumerated by either the two-matrix model used by physicists or by the bijection with blossom trees used by ...

متن کامل

An introduction to map enumeration Notes

1 Chapter 1: The oral tradition 3 1.1 Topological disclaimer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 Surfaces and graphs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Maps: three (four?) definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3.1 As embedded graphs. . . . . . . . . . . . . . . . . . . . . . . . . . . . ...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Discrete Mathematics

دوره 222  شماره 

صفحات  -

تاریخ انتشار 2000