 |
|
|
|
| HAL : hal-00277936, version 3 |
| arXiv : 0805.0987 |
| DOI : 10.1214/08-AIHP309 |
| Fiche détaillée |  Récupérer au format |
|
|
| Annales de l'IHP - Probabilités et Statistiques 46, 1 (2010) 72-96 |
|
|
| Versions disponibles : | v1 (07-05-2008) | v2 (10-12-2008) | v3 (16-12-2009) |
|
|
|
|
| On fine properties of mixtures with respect to concentration of measure and Sobolev type inequalities |
|
|
Djalil Chafai 1, 2Florent Malrieu 3 |
|
|
| (28/02/2010) |
|
|
|
| Mixtures are convex combinations of laws. Despite this simple definition, a mixture can be far more subtle than its mixed components. For instance, mixing Gaussian laws may produce a potential with multiple deep wells. We study in the present work fine properties of mixtures with respect to concentration of measure and Sobolev type functional inequalities. We provide sharp Laplace bounds for Lipschitz functions in the case of generic mixtures, involving a transportation cost diameter of the mixed family. Additionally, our analysis of Sobolev type inequalities for two-component mixtures reveals natural relations with some kind of band isoperimetry and support constrained interpolation via mass transportation. We show that the Poincaré constant of a two-component mixture may remain bounded as the mixture proportion goes to $0$ or $1$ while the logarithmic Sobolev constant may surprisingly blow up. This counter-intuitive result is not reducible to support disconnections, and appears as a reminiscence of the variance-entropy comparison on the two-point space. As far as mixtures are concerned, the logarithmic Sobolev inequality is less stable than the Poincaré inequality and the sub-Gaussian concentration for Lipschitz functions. We illustrate our results on a gallery of concrete two-component mixtures. This work leads to many open questions. |
|
|
|
|
|
|
|
|
|
|
|
| 1 : | Institut de Mathématiques de Toulouse (IMT) |
|
|
|
Université Paul Sabatier - Toulouse III – Université Toulouse le Mirail - Toulouse II – Université des Sciences Sociales - Toulouse I – Institut National des Sciences Appliquées de Toulouse – CNRS : UMR5219 |
|
|
| 2 : | Physiopathologie et Toxicologie Expérimentales (UPTE) |
|
|
|
INRA : UR0181 – Ecole Nationale Vétérinaire de Toulouse |
|
|
| 3 : | Institut de Recherche Mathématique de Rennes (IRMAR) |
|
|
|
CNRS : UMR6625 – Université de Rennes I – École normale supérieure de Cachan - ENS Cachan – Institut National des Sciences Appliquées de Rennes |
|
|
|
|
|
|
|
|
|
| Domaine | : | Mathématiques/Probabilités Mathématiques/Analyse fonctionnelle |
|
|
| Mixtures of distributions – finite Gaussian mixtures – concentration of measure – Gaussian bounds – tails probabilities – deviation inequalities – functional inequalities – Poincare inequalities – Gross logarithmic Sobolev inequalities – band isoperimetry – transportation of measure – mass transportation – transportation cost distances – Mallows or Wasserstein distance |
|
|
|
|
|
| hal-00277936, version 3 | |
| http://hal.archives-ouvertes.fr/hal-00277936/fr/ | |
| oai:hal.archives-ouvertes.fr:hal-00277936_v3 | |
| Contributeur : Djalil Chafai | |
| Soumis le : Mardi 15 Décembre 2009, 22:29:27 | |
| Dernière modification le : Dimanche 7 Mars 2010, 14:25:46 | |
