The Annals of Probability
- Ann. Probab.
- Volume 44, Number 3 (2016), 1601-1646.
The measurable Kesten theorem
We give an explicit bound on the spectral radius in terms of the densities of short cycles in finite $d$-regular graphs. It follows that the a finite $d$-regular Ramanujan graph $G$ contains a negligible number of cycles of size less than $c\log\log\vert G\vert$.
We prove that infinite $d$-regular Ramanujan unimodular random graphs are trees. Through Benjamini–Schramm convergence this leads to the following rigidity result. If most eigenvalues of a $d$-regular finite graph $G$ fall in the Alon–Boppana region, then the eigenvalue distribution of $G$ is close to the spectral measure of the $d$-regular tree. In particular, $G$ contains few short cycles.
In contrast, we show that $d$-regular unimodular random graphs with maximal growth are not necessarily trees.
Ann. Probab. Volume 44, Number 3 (2016), 1601-1646.
Received: February 2012
Revised: May 2014
First available in Project Euclid: 16 May 2016
Permanent link to this document
Digital Object Identifier
Mathematical Reviews number (MathSciNet)
Zentralblatt MATH identifier
Primary: 05C81: Random walks on graphs 60G50: Sums of independent random variables; random walks
Secondary: 82C41: Dynamics of random walks, random surfaces, lattice animals, etc. [See also 60G50]
Abért, Miklós; Glasner, Yair; Virág, Bálint. The measurable Kesten theorem. Ann. Probab. 44 (2016), no. 3, 1601--1646. doi:10.1214/14-AOP937. https://projecteuclid.org/euclid.aop/1463410029