Growth constants of minor-closed classes of graphs

  • Authors:
  • Olivier Bernardi;Marc Noy;Dominic Welsh

  • Affiliations:
  • CNRS, Département de Mathématiques, Université Paris-Sud, 91405 Orsay Cedex, France;Universitat Politècnica de Catalunya, Jordi Girona 1-3, 08034 Barcelona, Spain;University of Oxford, Mathematical Institute, 24-29 St Giles', Oxford OX1 3LB, UK

  • Venue:
  • Journal of Combinatorial Theory Series B
  • Year:
  • 2010

Quantified Score

Hi-index 0.00

Visualization

Abstract

A minor-closed class of graphs is a set of labelled graphs which is closed under isomorphism and under taking minors. For a minor-closed class G, let g"n be the number of graphs in G which have n vertices. The growth constant of G is @c=lim@?sup(g"n/n!)^1^/^n. We study the properties of the set @C of growth constants of minor-closed classes of graphs. Among other results, we show that @C does not contain any number in the interval [0,2], besides 0, 1, @x and 2, where @x~1.76. An infinity of further gaps is found by determining all the possible growth constants between 2 and @d~2.25159. Our results give in fact a complete characterization of all the minor-closed classes with growth constant at most @d in terms of their excluded minors.