{ "id": "1405.1583", "version": "v1", "published": "2014-05-07T12:18:31.000Z", "updated": "2014-05-07T12:18:31.000Z", "title": "The harmonic measure of balls in critical Galton-Watson trees with infinite variance offspring distribution", "authors": [ "Shen Lin" ], "comment": "46 pages, 4 figures. arXiv admin note: substantial text overlap with arXiv:1304.7190 by other authors", "categories": [ "math.PR" ], "abstract": "We study properties of the harmonic measure of balls in large critical Galton-Watson trees whose offspring distribution is in the domain of attraction of a stable distribution with index $\\alpha\\in (1,2]$. Here the harmonic measure refers to the hitting distribution of height $n$ by simple random walk on the critical Galton-Watson tree conditioned on non-extinction at generation $n$. For a ball of radius $n$ centered at the root, we prove that, although the size of the boundary is roughly of order $n^{\\frac{1}{\\alpha-1}}$, most of the harmonic measure is supported on a boundary subset of size approximately equal to $n^{\\beta_{\\alpha}}$, where the constant $\\beta_{\\alpha}\\in (0,\\frac{1}{\\alpha-1})$ depends only on the index $\\alpha$. Using an explicit expression of $\\beta_{\\alpha}$, we are able to show the uniform boundedness of $(\\beta_{\\alpha}, 1<\\alpha\\leq 2)$. These are generalizations of results in a recent paper of Curien and Le Gall (arXiv: 1304.7190).", "revisions": [ { "version": "v1", "updated": "2014-05-07T12:18:31.000Z" } ], "analyses": { "subjects": [ "60J80", "60G50", "60K37" ], "keywords": [ "infinite variance offspring distribution", "simple random walk", "large critical galton-watson trees", "harmonic measure refers", "uniform boundedness" ], "note": { "typesetting": "TeX", "pages": 46, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1405.1583L" } } }