This is an announcement for the paper "Concentration analysis in Banach spaces" by Sergio Solimini and Cyril Tintarev.
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.
Archive classification: math.FA
Mathematics Subject Classification: 46B20, 46B10, 46B50, 46B99
Submitted from: tintarev@math.uu.se
The paper may be downloaded from the archive by web browser from URL
http://front.math.ucdavis.edu/1502.00414
or
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alspach＠math.okstate.edu