We consider a class of Liouville equations that arise in differential geometry when prescribing the Gaussian curvature of a surface and in models of mathematical physics describing stationary Euler flows and self-dual Chern-Simons equations. We discuss methods, variational in nature, to derive general existence results from suitable improvements of the Moser-Trudinger inequality combined with Morse-theoretical methods. We will treat in particular the case with Dirac masses representing, in the above motivations, conical singularities or vortex points.

We consider a class of Liouville equations that arise in differential geometry when prescribing the Gaussian curvature of a surface and in models of mathematical physics describing stationary Euler flows and self-dual Chern-Simons equations. We discuss methods, variational in nature, to derive general existence results from suitable improvements of the Moser-Trudinger inequality combined with Morse-theoretical methods. We will treat in particular the case with Dirac masses representing, in the above motivations, conical singularities or vortex points.

On présente des modèles unidimensionnels et bidimensionnels de ferromagnétisme et de ferroélectricité obtenus par réduction de dimensions à partir de modèles tridimensionnels. Les modèles obtenus sont plus simples à traiter, surtout d'un point de vue numérique. On donne aussi quelques idées des démonstrations.