{ "id": "math/0604439", "version": "v1", "published": "2006-04-20T06:46:48.000Z", "updated": "2006-04-20T06:46:48.000Z", "title": "Regular variation in the branching random walk", "authors": [ "Aleksander Iksanov", "Sergey Polotskiy" ], "comment": "submitted", "categories": [ "math.PR" ], "abstract": "Let $\\{\\mm_n, n=0,1,...\\}$ be the supercritical branching random walk starting with one initial ancestor located at the origin of the real line. For $n=0,1,...$ let $W_n$ be the moment generating function of $\\mm_n$ normalized by its mean. Denote by $AW_n$ any of the following random variables: maximal function, square function, $L_1$ and a.s. limit $W$, $\\su |W-W_n|$, $\\su |W_{n+1}-W_n|$. Under mild moment restrictions and the assumption that $\\rP\\{W_1>x\\}$ regularly varies at $\\infty$ it is proved that $\\rP\\{AW_n>x\\}$ regularly varies at $\\infty$ with the same exponent. All the proofs given are non-analytic in the sense that these do not use Laplace-Stieltjes transforms. The result on the tail behaviour of $W$ is established in two distinct ways.", "revisions": [ { "version": "v1", "updated": "2006-04-20T06:46:48.000Z" } ], "analyses": { "subjects": [ "60G42", "60J80", "60E99" ], "keywords": [ "regular variation", "branching random walk starting", "mild moment restrictions", "regularly varies", "tail behaviour" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2006math......4439I" } } }