{ "id": "math/0410105", "version": "v1", "published": "2004-10-05T17:08:37.000Z", "updated": "2004-10-05T17:08:37.000Z", "title": "Limit theorems for a class of identically distributed random variables", "authors": [ "Patrizia Berti", "Luca Pratelli", "Pietro Rigo" ], "comment": "Published by the Institute of Mathematical Statistics (http://www.imstat.org) in the Annals of Probability (http://www.imstat.org/aop/) at http://dx.doi.org/10.1214/009117904000000676", "journal": "Annals of Probability 2004, Vol. 32, No. 3A, 2029-2052", "doi": "10.1214/009117904000000676", "categories": [ "math.PR" ], "abstract": "A new type of stochastic dependence for a sequence of random variables is introduced and studied. Precisely, (X_n)_{n\\geq 1} is said to be conditionally identically distributed (c.i.d.), with respect to a filtration (G_n)_{n\\geq 0}, if it is adapted to (G_n)_{n\\geq 0} and, for each n\\geq 0, (X_k)_{k>n} is identically distributed given the past G_n. In case G_0={\\varnothing,\\Omega} and G_n=\\sigma(X_1,...,X_n), a result of Kallenberg implies that (X_n)_{n\\geq 1} is exchangeable if and only if it is stationary and c.i.d. After giving some natural examples of nonexchangeable c.i.d. sequences, it is shown that (X_n)_{n\\geq 1} is exchangeable if and only if (X_{\\tau(n)})_{n\\geq 1} is c.i.d. for any finite permutation \\tau of {1,2,...}, and that the distribution of a c.i.d. sequence agrees with an exchangeable law on a certain sub-\\sigma-field. Moreover, (1/n)\\sum_{k=1}^nX_k converges a.s. and in L^1 whenever (X_n)_{n\\geq 1} is (real-valued) c.i.d. and E[| X_1| ]<\\infty. As to the CLT, three types of random centering are considered. One such centering, significant in Bayesian prediction and discrete time filtering, is E[X_{n+1}| G_n]. For each centering, convergence in distribution of the corresponding empirical process is analyzed under uniform distance.", "revisions": [ { "version": "v1", "updated": "2004-10-05T17:08:37.000Z" } ], "analyses": { "subjects": [ "60B10", "60G09", "60F05", "60F15" ], "keywords": [ "identically distributed random variables", "limit theorems", "finite permutation", "kallenberg implies", "natural examples" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2004math.....10105B" } } }