We investigate the relationship between geometric, analytic and probabilistic indices for quotients of the Cayley graph of the free group Cay.Fn/ by an arbitrary subgroup G of Fn. Our main result, which generalizes Grigorchuk’s cogrowth formula to variable edge lengths, provides a formula relating the bottom of the spectrum of weighted Laplacian on Gn Cay.Fn/ to the Poincaré exponent of G. Our main tool is the Patterson–Sullivan theory for metric trees.
ASJC Scopus subject areas
- Geometry and Topology
- Discrete Mathematics and Combinatorics