Pointwise Fourier Inversion on Tori and Other Compact Manifolds.
While the physical properties of the gravitational field in the radiation regime are reasonably well understood, several mathematical questions remain unanswered. The question here is that of existence and properties of gravitational fields with asymptotic behavior compatible with existence of gravitational radiation. A framework to study those questions has been proposed by R. Penrose (R. Penrose, “Zero rest-mass fields including gravitation”, Proc. Roy. Soc. London A284 (1965), 159-203), and developed...
The purpose of this article is to introduce for dispersive partial differential equations with random initial data, the notion of well-posedness (in the Hadamard-probabilistic sense). We restrict the study to one of the simplest examples of such equations: the periodic cubic semi-linear wave equation. Our contributions in this work are twofold: first we break the algebraic rigidity involved in our previous works and allow much more general randomizations (general infinite product measures v.s. Gibbs...
In questa conferenza descrivo alcuni recenti sviluppi relativi al problema dell'unicità per l'equazione differenziale ordinaria e per l'equazione di continuità per campi vettoriali debolmente differenziabili. Descrivo infine un'applicazione di questi risultati a un sistema di leggi di conservazione.
Ce travail est consacré à l’étude du problème mixte linéaire pour un système non caractéristique, strictement hyperbolique, de degré 1, dans le cas où la condition aux limites présente un saut sur une hypersurface non caractéristique du bord. Sous la condition de Lopatinski uniforme hors de cette hypersurface et sous une hypothèse supplémentaire le long de celle-ci, on prouve un résultat d’existence et d’unicité dans l’espace de Sobolev . On étudie ensuite la propagation de la régularité conormale...