On the number of planar Eulerian orientations

Autor: Claire Pennarun, Mireille Bousquet-Mélou, Paul Dorbec, Nicolas Bonichon
Přispěvatelé: Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB), Centre National de la Recherche Scientifique (CNRS), ANR-12-JS02-0002,EGOS,Graphes Plongés et leurs Structures Orientées(2012), ANR-14-CE25-0014,GRAAL,GRaphes et Arbres ALéatoires(2014)
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: European Journal of Combinatorics
European Journal of Combinatorics, Elsevier, 2017, 65, pp.59-91
HAL
ISSN: 0195-6698
1095-9971
Popis: The number of planar Eulerian maps with n edges is well-known to have a simple expression. But what is the number of planar Eulerian orientations with n edges? This problem appears to be a difficult one. To approach it, we define and count families of subsets and supersets of planar Eulerian orientations, indexed by an integer k , that converge to the set of all planar Eulerian orientations as k increases. The generating functions of our subsets can be characterized by systems of polynomial equations, and are thus algebraic. The generating functions of our supersets are characterized by polynomial systems involving divided differences, as often occurs in map enumeration. We prove that these series are algebraic as well. We obtain in this way lower and upper bounds on the growth rate of planar Eulerian orientations, which appears to be around 12.5.
Databáze: OpenAIRE