Régularité höldérienne de certains problèmes aux limites elliptiques singuliers
On étudie la régularité microlocale de type Sobolev au voisinage du bord d’un ouvert de pour des solutions réelles d’un problème aux limites non linéaire non caractéristique dans la zone à comportement linéaire decrite par J. M. Bony : au delà des chocs et en dessous de l’interaction. Pour ces solutions le front d’onde au bord est bien défini et ne contient pas les points de bord elliptiques au sens de Melrose pour le linéarisé sur la solution, si celle-ci vérifie des conditions aux limites régulières....
This paper is devoted to the study of the regularity of solutions to some systems of reaction–diffusion equations. In particular, we show the global boundedness and regularity of the solutions in one and two dimensions. In addition, we discuss the Hausdorff dimension of the set of singularities in higher dimensions. Our approach is inspired by De Giorgi’s method for elliptic regularity with rough coefficients. The proof uses the specific structure of the system to be considered and is not a mere...
We review some recent results for a class of fluid mechanics equations called active scalars, with fractional dissipation. Our main examples are the surface quasi-geostrophic equation, the Burgers equation, and the Cordoba-Cordoba-Fontelos model. We discuss nonlocal maximum principle methods which allow to prove existence of global regular solutions for the critical dissipation. We also recall what is known about the possibility of finite time blow...
We prove the existence and uniqueness of global strong solutions to the Cauchy problem for 3D incompressible MHD equations with nonlinear damping terms. Moreover, the preliminary L² decay for weak solutions is also established.