{ "id": "1305.6069", "version": "v1", "published": "2013-05-26T20:20:46.000Z", "updated": "2013-05-26T20:20:46.000Z", "title": "Uniform convexity of paranormed generalizations of $L^p$ spaces", "authors": [ "Justyna Jarczyk", "Janusz Matkowski" ], "comment": "30 pages", "categories": [ "math.FA" ], "abstract": "For a measure space $(\\Omega ,\\Sigma ,\\mu)$ and a bijective increasing function $\\varphi :\\left[ 0,\\infty \\right) \\rightarrow \\left[0,\\infty \\right)$ the $L^{p}$-like paranormed ($F$-normed) function space with the paranorm of the form $\\mathbf{p}_{\\varphi}(x)=\\varphi ^{-1}\\left(\\int_{\\Omega}\\varphi \\circ \\left|x\\right|d\\mu \\right)$ is considered. Main results give general conditions under which this space is uniformly convex. The Clarkson theorem on the uniform convexity of $L^{p}$-space is generalized. Under some specific assumptions imposed on $\\varphi$ we give not only a proof of the uniform convexity but also show the formula of a modulus of convexity. We establish the uniform convexity of all finite-dimensional paranormed spaces, generated by a strictly convex bijection $\\varphi$ of $[0, \\infty)$. However, the {\\it a contrario} proof of this fact provides no information on a modulus of convexity of these spaces. In some cases it can be done, even an exact formula of a modulus can be proved. We show how to make it in the case when $S={\\mathbb R}^2$ and $\\varphi$ is given by $\\varphi(t)={\\rm e}^t-1$.", "revisions": [ { "version": "v1", "updated": "2013-05-26T20:20:46.000Z" } ], "analyses": { "subjects": [ "46A16", "46E30", "47H09", "47H10" ], "keywords": [ "uniform convexity", "paranormed generalizations", "strictly convex bijection", "function space", "exact formula" ], "note": { "typesetting": "TeX", "pages": 30, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2013arXiv1305.6069J" } } }