Radial Averages on Regular and Semiregular Graphs

TL;DR

This paper extends classical hyperbolic surface averaging results to regular and semiregular graphs, analyzing convergence of averages over various geometric sets with a focus on rates.

Contribution

It introduces new averaging techniques on graphs over general sets like spherical arcs, tubes, and horocycles, with detailed convergence rate analysis.

Findings

Averages over spherical arcs converge similarly to those over spheres.

Results include convergence rates for averages over tubes and horocycles.

Provides a unified framework for averaging on graphs and hyperbolic surfaces.

Abstract

In 1966, P. G\"unther proved the following result: Given a continuous function $f$ on a compact surface $M$ of constant curvature -1 and its periodic lift $\tilde{f}$ to the universal covering, the hyperbolic plane, then the averages of the lift $\tilde{f}$ over increasing spheres converge to the average of the function $f$ over the surface $M$. In this article, we prove similar results for functions on the vertices and edges of regular and semiregular graphs, with special emphasis on the convergence rate. However, we consider averages over more general sets, namely spherical arcs, which in turn imply results for tubes and horocycles as well as spheres.