{ "id": "1502.00414", "version": "v1", "published": "2015-02-02T09:20:43.000Z", "updated": "2015-02-02T09:20:43.000Z", "title": "Concentration analysis in Banach spaces", "authors": [ "Sergio Solimini", "Cyril Tintarev" ], "categories": [ "math.FA" ], "abstract": "The concept of a profile decomposition formalizes concentration compactness arguments on the functional-analytic level, providing a powerful refinement of the Banach-Alaoglu weak-star compactness theorem. We prove existence of profile decompositions for general bounded sequences in uniformly convex Banach spaces equipped with a group of bijective isometries, thus generalizing analogous results previously obtained for Sobolev spaces and for Hilbert spaces. Profile decompositions in uniformly convex Banach spaces are based on the notion of $\\Delta$-convergence by T. C. Lim instead of weak convergence, and the two modes coincide if and only if the norm satisfies the well-known Opial condition, in particular, in Hilbert spaces and $\\ell^{p}$-spaces, but not in $L^{p}(\\mathbb R^{N})$, $p\\neq2$. $\\Delta$-convergence appears naturally in the context of fixed point theory for non-expansive maps. The paper also studies connection of $\\Delta$-convergence with Brezis-Lieb Lemma and gives a version of the latter without an assumption of convergence a.e.", "revisions": [ { "version": "v1", "updated": "2015-02-02T09:20:43.000Z" } ], "analyses": { "subjects": [ "46B20", "46B10", "46B50", "46B99" ], "keywords": [ "concentration analysis", "uniformly convex banach spaces", "convergence", "profile decomposition" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150200414S" } } }