{ "id": "1107.3760", "version": "v1", "published": "2011-07-19T16:20:00.000Z", "updated": "2011-07-19T16:20:00.000Z", "title": "On the density of exponential functionals of Lévy processes", "authors": [ "Juan Carlos Pardo", "Victor Rivero", "Kees van Schaik" ], "comment": "9 figures", "categories": [ "math.PR" ], "abstract": "In this paper, we study the existence of the density associated to the exponential functional of the L\\'evy process $\\xi$, \\[ I_{\\ee_q}:=\\int_0^{\\ee_q} e^{\\xi_s} \\, \\mathrm{d}s, \\] where $\\ee_q$ is an independent exponential r.v. with parameter $q\\geq 0$. In the case when $\\xi$ is the negative of a subordinator, we prove that the density of $I_{\\ee_q}$, here denoted by $k$, satisfies an integral equation that generalizes the one found by Carmona et al. \\cite{Carmona97}. Finally when $q=0$, we describe explicitly the asymptotic behaviour at 0 of the density $k$ when $\\xi$ is the negative of a subordinator and at $\\infty$ when $\\xi$ is a spectrally positive L\\'evy process that drifts to $+\\infty$.", "revisions": [ { "version": "v1", "updated": "2011-07-19T16:20:00.000Z" } ], "analyses": { "subjects": [ "60G51" ], "keywords": [ "exponential functional", "lévy processes", "independent exponential", "subordinator", "integral equation" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2011arXiv1107.3760P" } } }