{ "id": "1509.09261", "version": "v1", "published": "2015-09-30T17:20:58.000Z", "updated": "2015-09-30T17:20:58.000Z", "title": "Polar decomposition of scale-homogeneous measures with application to Lévy measures of strictly stable laws", "authors": [ "Steven N. Evans", "Ilya Molchanov" ], "comment": "22 pages", "categories": [ "math.PR" ], "abstract": "A scaling on some space is a measurable action of the group of positive real numbers. A measure on a measurable space equipped with a scaling is said to be $\\alpha$-homogeneous for some nonzero real number $\\alpha$ if the mass of any measurable set scaled by any factor $t > 0$ is the multiple $t^{-\\alpha}$ of the set's original mass. It is shown rather generally that given an $\\alpha$-homogeneous measure on a measurable space there is a measurable bijection between the space and the Cartesian product of a subset of the space and the positive real numbers (that is, a \"system of polar coordinates\") such that the push-forward of the $\\alpha$-homogeneous measure by this bijection is the product of a probability measure on the first component (that is, on the \"angular\" component) and an $\\alpha$-homogeneous measure on the positive half-line (that is, on the \"radial\" component). This result is applied to the intensity measures of Poisson processes that arise in L\\'evy-Khinchin-It\\^o-like representations of infinitely divisible random elements. It is established that if a strictly stable random element in a convex cone admits a series representation as the sum of points of a Poisson process, then it necessarily has a LePage representation as the sum of i.i.d. random elements of the cone scaled by the successive points of an independent unit intensity Poisson process on the positive half-line each raised to the power $-\\frac{1}{\\alpha}$.", "revisions": [ { "version": "v1", "updated": "2015-09-30T17:20:58.000Z" } ], "analyses": { "subjects": [ "28A50", "28C10", "60B15", "60E07" ], "keywords": [ "strictly stable laws", "lévy measures", "polar decomposition", "scale-homogeneous measures", "random element" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable" } } }