Counting overlattices in automorphism groups of trees
Abstract
Description
We give an upper bound for the number of ``overlattices'' in the automorphism group of a tree, containing a fixed lattice with index n. For an example of a lattice in the automorphism group of a 2p-regular tree whose quotient is a loop, we obtain a lower bound of the asymptotic behavior as well.
16 pages, to appear in Geom. Dedicata
16 pages, to appear in Geom. Dedicata