{ "id": "1309.0689", "version": "v1", "published": "2013-09-03T14:16:23.000Z", "updated": "2013-09-03T14:16:23.000Z", "title": "Subnormal weighted shifts on directed trees and composition operators in $L^2$ spaces with non-densely defined powers", "authors": [ "Piotr Budzynski", "Piotr Dymek", "Zenon Jan Jablonski", "Jan Stochel" ], "categories": [ "math.FA" ], "abstract": "It is shown that for every positive integer $n$ there exists a subnormal weighted shift on a directed tree (with or without root) whose $n$th power is densely defined while its $(n+1)$th power is not. As a consequence, for every positive integer $n$ there exists a non-symmetric subnormal composition operator $C$ in an $L^2$ space over a $\\sigma$-finite measure space such that $C^n$ is densely defined and $C^{n+1}$ is not.", "revisions": [ { "version": "v1", "updated": "2013-09-03T14:16:23.000Z" } ], "analyses": { "subjects": [ "47B20", "47B37", "47B33" ], "keywords": [ "subnormal weighted shift", "non-densely defined powers", "directed tree", "non-symmetric subnormal composition operator", "th power" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1309.0689B" } } }