{ "id": "2401.15373", "version": "v1", "published": "2024-01-27T10:37:24.000Z", "updated": "2024-01-27T10:37:24.000Z", "title": "Compactness of averaging operators on Banach function spaces", "authors": [ "Katsuhisa Koshino" ], "categories": [ "math.FA" ], "abstract": "Let $X$ be a Borel metric measure space such that each closed ball is of positive and finite measure. In this paper, we give a sufficient and necessary condition for averaging operators on a Banach function space $E(X)$ on $X$ to be compact. As a corollary, we show that the averaging operators on the Lorentz space $L^{p,q}(X)$ of $X$ is compact if and only if $X$ is bounded, in the case where $X$ is a doubling and Borel-regular metric measure space with some continuity between metric and measure.", "revisions": [ { "version": "v1", "updated": "2024-01-27T10:37:24.000Z" } ], "analyses": { "subjects": [ "47B01", "46E30" ], "keywords": [ "banach function space", "averaging operators", "compactness", "borel metric measure space", "borel-regular metric measure space" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }