{ "id": "1209.4988", "version": "v2", "published": "2012-09-22T11:41:20.000Z", "updated": "2013-06-13T19:33:36.000Z", "title": "Measurable events indexed by products of trees", "authors": [ "Pandelis Dodos", "Vassilis Kanellopoulos", "Konstantinos Tyros" ], "comment": "37 pages, no figures; Combinatorica, to appear. This article is a sequel to and draws heavily from arXiv:1105.2419", "categories": [ "math.CO" ], "abstract": "A tree $T$ is said to be homogeneous if it is uniquely rooted and there exists an integer $b\\meg 2$, called the branching number of $T$, such that every $t\\in T$ has exactly $b$ immediate successors. A vector homogeneous tree $\\mathbf{T}$ is a finite sequence $(T_1,...,T_d)$ of homogeneous trees and its level product $\\otimes\\mathbf{T}$ is the subset of the cartesian product $T_1\\times ...\\times T_d$ consisting of all finite sequences $(t_1,...,t_d)$ of nodes having common length. We study the behavior of measurable events in probability spaces indexed by the level product $\\otimes\\mathbf{T}$ of a vector homogeneous tree $\\mathbf{T}$. We show that, by refining the index set to the level product $\\otimes\\mathbf{S}$ of a vector strong subtree $\\bfcs$ of $\\mathbf{S}$, such families of events become highly correlated. An analogue of Lebesgue's density Theorem is also established which can be considered as the \"probabilistic\" version of the density Halpern--L\\\"{a}uchli Theorem.", "revisions": [ { "version": "v2", "updated": "2013-06-13T19:33:36.000Z" } ], "analyses": { "keywords": [ "measurable events", "level product", "vector homogeneous tree", "finite sequence", "lebesgues density theorem" ], "note": { "typesetting": "TeX", "pages": 37, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2012arXiv1209.4988D" } } }