J. Aust. Math. Soc.  73 (2002), 301-333
Limit theorems for isotropic random walks on triangle buildings

Marc Lindlbauer
  Mathematisches Institut
  Universität Tübingen
  Auf der Morgenstelle 10
  72076 Tübingen
  Germany
  and
  GSF-Forschungszentrum
  für Umwelt und Gesundheit
  85764 Neuherberg
  Germany
 
and
Michael Voit
  Mathematisches Institut
  Universität Tübingen
  Auf der Morgenstelle 10
  72076 Tübingen
  Germany
  michael.voit@uni-tuebingen.de


Abstract
The spherical functions of triangle buildings can be described in terms of certain two-dimensional orthogonal polynomials on Steiner's hypocycloid which are closely related to Hall-Littlewood polynomials. They lead to a one-parameter family of two-dimensional polynomial hypergroups. In this paper we investigate isotropic random walks on the vertex sets of triangle buildings in terms of their projections to these hypergroups. We present strong laws of large numbers, a central limit theorem, and a local limit theorem; all these results are well-known for homogeneous trees. Proofs are based on moment functions on hypergroups and on explicit expansions of the hypergroup characters in terms of certain two-dimensional Tchebychev polynomials.
Download the article in PDF format (size 276 Kb)

TeXAdel Scientific Publishing ©  Australian MS