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Mario Milman

Publications and source records attributed to Mario Milman.

33 records · Page 2Linked to original sources

Nigel Kalton and the interpolation theory of commutators

This is the second of a series of papers surveying some small part of the remarkable work of our friend and colleague Nigel Kalton. We have written it as part of a tribute to his memory. It does not contain new results. One of the many topics in which Nigel made very significant and profound contributions deals with commutators in interpolation theory. It was our great privilege to work with him on one of his many papers about this topic. Our main purpose here is to offer} an introduction to that paper: A unified theory of commutator estimates for a class of interpolation methods. Adv. Math. 169 (2002), no. 2, 241--312. We sketch the theory of interpolation spaces constructed using pseudolattices which was developed in that paper and which enables quite general formulation of commutator theorems. We seek to place the results of that paper in the general context of preceding and subsequent research on this topic, also indicating some applications to other fields of analysis and possible directions for future research.

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Towards a unified theory of Sobolev inequalities

We discuss our work on pointwise inequalities for the gradient which are connected with the isoperimetric profile associated to a given geometry. We show how they can be used to unify certain aspects of the theory of Sobolev inequalities. In particular, we discuss our recent papers on fractional order inequalities, Coulhon type inequalities, transference and dimensionless inequalities and our forthcoming work on sharp higher order Sobolev inequalities that can be obtained by iteration.

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An introduction to Nigel Kalton's work on differentials of complex interpolation processes for Kothe spaces

This paper contains no new results. It is intended to be merely a brief introduction to the long paper: N. J. Kalton, Differentials of complex interpolation processes for Kothe function spaces. Trans. Amer. Math. Soc. 333 (1992), no. 2, 479--529. and to mention some possible directions for applying the powerful methods developed in Kalton's paper for further future research. The reader should also be aware of other perspectives in other commentaries on Kalton's paper, which appear in other sources to which we refer.

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Fractional Sobolev Inequalities: Symmetrization, Isoperimetry and Interpolation

We obtain new oscillation inequalities in metric spaces in terms of the Peetre $K-$functional and the isoperimetric profile. Applications provided include a detailed study of Fractional Sobolev inequalities and the Morrey-Sobolev embedding theorems in different contexts. In particular we include a detailed study of Gaussian measures as well as probablity measures between Gaussian and exponential. We show a kind of reverse Polya-Szego principle that allows us to obtain continuity as a self improvement from boundedness, using symetrization inequalities. Our methods also allow for precise estimates of growth envelopes of generalized Sobolev and Besov spaces on metric spaces. We also consider embeddings into $BMO$ and their connection to Sobolev embeddings.

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Integral isoperimetric transference and dimensionless Sobolev inequalities

We introduce the concept of Gaussian integral isoperimetric transference and show how it can be applied to obtain a new class of sharp Sobolev-Poincaré inequalities with constants independent of the dimension. In the special case of $L^{q}$ spaces on the unit $n-$dimensional cube our results extend the recent inequalities that were obtained in \cite{FKS} using extrapolation.

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A Note on Coulhon type inequalities

T. Coulhon introduced an interesting reformulation of the usual Sobolev inequalities. We characterize Coulhon type inequalities in terms of rearrangement inequalities.

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Isoperimetry and Symmetrization for Sobolev spaces on metric spaces

Using isoperimetry we obtain new symmetrization inequalities that allow us to provide a unified framework to study Sobolev inequalities in metric spaces. The applications include concentration inequalities, as well as metric versions of the Pó% lya-Szegö and Faber-Krahn principles.

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Isoperimetry and symmetrization for logarithmic Sobolev inequalities

Using isoperimetry and symmetrization we provide a unified framework to study the classical and logarithmic Sobolev inequalities. In particular, we obtain new Gaussian symmetrization inequalities and connect them with logarithmic Sobolev inequalities. Our methods are very general and can be easily adapted to more general contexts.

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