Einstein gravity, Lagrange-Finsler geometry, and nonsymmetric metrics.
Energy and Morse index of solutions of Yamabe type problems on thin annuli
We consider the Yamabe type family of problems , in , on , where is an annulus-shaped domain of , , which becomes thinner as . We show that for every solution , the energy as well as the Morse index tend to infinity as . This is proved through a fine blow up analysis of appropriate scalings of solutions whose limiting profiles are regular, as well as of singular solutions of some elliptic problem on , a half-space or an infinite strip. Our argument also involves a Liouville type theorem...
Energy quantization for Yamabe's problem in conformal dimension.
Entropy of eigenfunctions of the Laplacian in dimension 2
We study asymptotic properties of eigenfunctions of the Laplacian on compact Riemannian surfaces of Anosov type (for instance negatively curved surfaces). More precisely, we give an answer to a question of Anantharaman and Nonnenmacher [4] by proving that the Kolmogorov-Sinai entropy of a semiclassical measure for the geodesic flow is bounded from below by half of the Ruelle upper bound. (This text has been written for the proceedings of the Journées EDP (Port d’Albret-June, 7-11 2010))
Estimates of the first eigenvalue of a big cup domain of a 2-sphere
Estimation of the visibility angle of a curve in a metric space of nonpositive curvature.
Estimation of vibration frequencies of linear elastic membranes
The free motion of a thin elastic linear membrane is described, in a simplyfied model, by a second order linear homogeneous hyperbolic system of partial differential equations whose spatial part is the Laplace Beltrami operator acting on a Riemannian 2-dimensional manifold with boundary. We adapt the estimates of the spectrum of the Laplacian obtained in the last years by several authors for compact closed Riemannian manifolds. To make so, we use the standard technique of the doubled manifold to...
Evolution of curvature tensors under mean curvature flow.
Evolution of hypersurfaces by their curvature in Riemannian manifolds.
Existence of metrics with harmonic curvature and non parallel Ricci tensor.
Existence of positive harmonic functions on groups and on covering manifolds
Existence results for the prescribed Scalar curvature on
This paper is devoted to the existence of conformal metrics on with prescribed scalar curvature. We extend well known existence criteria due to Bahri-Coron.
Extremal domains for the first eigenvalue of the Laplace-Beltrami operator
We prove the existence of extremal domains with small prescribed volume for the first eigenvalue of Laplace-Beltrami operator in some Riemannian manifold. These domains are close to geodesic spheres of small radius centered at a nondegenerate critical point of the scalar curvature.