Comportement semi-classique des systèmes ergodiques
Composition of some singular Fourier integral operators and estimates for restricted -ray transforms
We establish a composition calculus for Fourier integral operators associated with a class of smooth canonical relations . These canonical relations, which arise naturally in integral geometry, are such that : is a Whitney fold and : is a blow-down mapping. If , , then a class of pseudodifferential operators with singular symbols. From this follows boundedness of with a loss of 1/4 derivative.
Concentration of the Brownian bridge on Cartan-Hadamard manifolds with pinched negative sectional curvature
We study the rate of concentration of a Brownian bridge in time one around the corresponding geodesical segment on a Cartan-Hadamard manifold with pinched negative sectional curvature, when the distance between the two extremities tends to infinity. This improves on previous results by A. Eberle, and one of us . Along the way, we derive a new asymptotic estimate for the logarithmic derivative of the heat kernel on such manifolds, in bounded time and with one space parameter...
Conditional expectations for derivatives of certain stochastic flows
Conditions de Bohr-Sommerfeld pour les singularités focus-focus et monodromie quantique
Je présenterai les résultats d’une étude microlocale détaillée du spectre joint de deux opérateurs h-pseudo-différentiels qui commutent sur une variété de dimension deux en présence d’une singularité dite «focus-focus». L’étude couvre par exemple le cas du pendule sphérique étudié par Duistermaat, ou du fond de la bouteille de champagne, mais les phénomènes observés sont universels. On en observe principalement deux: une accumulation de valeurs propres au voisinage de la singularité en par rapport...
Conditions de positivité dans une variété symplectique complexe. Applications à l'étude de l'hypoellipticité analytique
Conditions de positivité dans une variété symplectique complexe. Application à l'étude des microfonctions
Conditions for global existence of solutions of ordinary differential, stochastic differential, and parabolic equations.
Cônes symplectiques et opérateurs de Toeplitz
Confomal deformations on a noncompact Riemannian manifold.
Conformal Dirichlet-Neumann maps and Poincaré-Einstein manifolds.
Conformal Geometry and the Composite Membrane Problem
We show that a certain eigenvalue minimization problem in two dimensions for the Laplace operator in conformal classes is equivalent to the composite membrane problem. We again establish such a link in higher dimensions for eigenvalue problems stemming from the critical GJMS operators. New free boundary problems of unstable type arise in higher dimensions linked to the critical GJMS operator. In dimension four, the critical GJMS operator is exactly the Paneitz operator.
Conformal gradient vector fields on a compact Riemannian manifold
It is proved that if an n-dimensional compact connected Riemannian manifold (M,g) with Ricci curvature Ric satisfying 0 < Ric ≤ (n-1)(2-nc/λ₁)c for a constant c admits a nonzero conformal gradient vector field, then it is isometric to Sⁿ(c), where λ₁ is the first nonzero eigenvalue of the Laplacian operator on M. Also, it is observed that existence of a nonzero conformal gradient vector field on an n-dimensional compact connected Einstein manifold forces it to...
Conformal indices of riemannian manifolds
Conformal metrics with constant -curvature.
Conformal scalar curvature on the hyperbolic space.
Conformally bending three-manifolds with boundary
Given a three-dimensional manifold with boundary, the Cartan-Hadamard theorem implies that there are obstructions to filling the interior of the manifold with a complete metric of negative curvature. In this paper, we show that any three-dimensional manifold with boundary can be filled conformally with a complete metric satisfying a pinching condition: given any small constant, the ratio of the largest sectional curvature to (the absolute value of) the scalar curvature is less than this constant....
Conformally flat manifolds, Kleinian groups and scalar curvature.
Conic degeneration of the Dirac operator
Conjoint spectral asymptotics for the families of commuting operators and for operators with the periodic hamiltonian flow