S. Brofferio

Learn More
We consider the processes obtained by (left and right) products of random i.i.d. affine transformations of the Euclidean space R. Our main goal is to describe the geometrical behavior at infinity of the trajectories of these processes in the most critical case when the dilatation of the random affinities is centered. Then we derive a proof of the uniqueness(More)
We determine all positive harmonic functions for a large class of “semiisotropic” random walks on the lamplighter group, i.e., the wreath product Zq ≀Z, where q ≥ 2. This is possible via the geometric realization of a Cayley graph of that group as the Diestel-Leader graph DL(q, q). More generally, DL(q, r) (q, r ≥ 2) is the horocyclic product of two(More)
We determine the precise asymptotic behaviour (in space) of the Green kernel of simple random walk with drift on the Diestel–Leader graph DL(q, r), where q, r 2. The latter is the horocyclic product of two homogeneous trees with respective degrees q + 1 and r + 1. When q = r , it is the Cayley graph of the wreath product (lamplighter group) Zq Z with(More)
We present simple proofs of transience/recurrence for certain card shuffling models, that is, random walks on the infinite symmetric group. 1. Card shuffling models In this note, we consider several models of shuffling an infinite deck of cards. One of these models has been considered previously by Lawler [La]; our methods (using flows, shorting and(More)
We construct the Poisson boundary for a random walk supported by the general linear group on the rational numbers as the product of flag manifolds over the p-adic fields. To this purpose, we prove a law of large numbers using the Oseledets’ multiplicative ergodic theorem. The only assumption we need is some moment condition on the measure governing the(More)
The paper presents the work in progress of the design and implementation of an interactive system for the detection of the building's roofing characteristic. For each of its pitches data concerning height, shape, orientation, slope and useful area are estimated at different precision levels. The system operates on a cartographic map and two pre-processed(More)
  • 1