{"paper":{"title":"A multiplicative property characterizes quasinormal composition operators in $L^2$-spaces","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"math.FA","authors_text":"Il Bong Jung, Jan Stochel, Piotr Budzynski, Zenon Jan Jablonski","submitted_at":"2012-07-11T13:40:02Z","abstract_excerpt":"A densely defined composition operator in an $L^2$-space induced by a measurable transformation $\\phi$ is shown to be quasinormal if and only if the Radon-Nikodym derivatives $h_{\\phi^n}$ attached to powers $\\phi^n$ of $\\phi$ have the multiplicative property: $h_{\\phi^n} = h_{\\phi}^n$ almost everywhere for n = 0, 1, 2, ...."},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1207.2638","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}