Barycenters of measures transported by stochastic flows

• 成果类型: Article
• 署名作者: Arnaudon, M; Li, XM
• 署名单位: Universite de Poitiers; Nottingham Trent University
• 刊物名称: ANNALS OF PROBABILITY
• ISSN/ISSBN: 0091-1798
• DOI: 10.1214/009117905000000071
• 发表日期: 2005
• 页码: 1509-1543
• 关键词: probability; martingales; convexity; MANIFOLDS

摘要

We investigate the evolution of barycenters of masses transported by stochastic flows. The state spaces under consideration are smooth affine manifolds with certain convexity structure. Under suitable conditions on the flow and on the initial measure, the barycenter {Z} is shown to be a semimartingale and is described by a stochastic differential equation. For the hyperbolic space the barycenter of two independent Brownian particles is a martingale and its conditional law converges to that of a Brownian motion on the limiting geodesic. On the other hand for a large family of discrete measures on suitable Cartan-Hadamard manifolds, the barycenter of the measure carried by an unstable Brownian flow converges to the Busemann barycenter of the limiting measure.