{ "id": "2110.01233", "version": "v2", "published": "2021-10-04T07:53:27.000Z", "updated": "2023-06-26T11:47:14.000Z", "title": "Poisson-Orlicz norm and infinite Ergodic Theory", "authors": [ "Emmanuel Roy" ], "categories": [ "math.DS", "math.PR" ], "abstract": "Urbanik's theorem for a Poisson process on an infinite measure space (X, A, $\\mu$) relates integrability of stochastic integrals to a particular Orlicz function space L$\\Phi$ ($\\mu$) on which the L1-norm of the Poisson process induces a norm (called Poisson-Orlicz in the sequel) that is shown to be equivalent to the classical gauge and Orlicz norms.We obtain a full characterization of stochastic integrals using difference operators that, together with a simple duality argument, allows to derive Urbanik's theorem as well as an optimal inequality between the Orlicz and the Poisson-Orlicz norm.In a second part, we show that the Poisson-Orlicz norm plays a role in infinite Ergodic Theory where it is seen as an alternative to the L1-norm to identify several dynamical invariants that the latter fails to identify. We also show that, whereas the L1-norm fully characterizes exact endomorphisms (Lin's theorem), Poisson-Orlicz norm fully characterizes remotely infinite endomorphisms.", "revisions": [ { "version": "v2", "updated": "2023-06-26T11:47:14.000Z" } ], "analyses": { "keywords": [ "infinite ergodic theory", "poisson-orlicz norm", "characterizes remotely infinite endomorphisms", "fully characterizes exact endomorphisms", "fully characterizes remotely infinite" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }