Zobrazeno 1 - 10
of 37
pro vyhledávání: '"Soufi, Ahmad El"'
We study the eigenvalues of the magnetic Schroedinger operator associated with a magnetic potential A and a scalar potential q, on a compact Riemannian manifold M, with Neumann boundary conditions if the boundary is not empty. We obtain several bound
Externí odkaz:
http://arxiv.org/abs/1709.09482
Let M be a compact Riemannian manifold with boundary. Let b>0 be the number of connected components of its boundary. For manifolds of dimension at least 3, we prove that it is possible to obtain an arbitrarily large (b+1)-th Steklov eigenvalue using
Externí odkaz:
http://arxiv.org/abs/1701.04125
Autor:
Colbois, Bruno, Soufi, Ahmad El
Given a compact Riemannian manifold (M, g) and two positive functions $\rho$ and $\sigma$, we are interested in the eigenvalues of the Dirichlet energy functional weighted by $\sigma$, with respect to the L 2 inner product weighted by $\rho$. Under s
Externí odkaz:
http://arxiv.org/abs/1606.04095
Autor:
Aribi, Amine, Soufi, Ahmad El
We prove that the first positive eigenvalue, normalized by the volume, of the sub-Laplacian associated with a strictly pseudoconvex pseudo-Hermitian structure $\\theta$ on the CR sphere S 2n+1 $\subset$ C n+1 , achieves its maximum when $\\theta$ is
Externí odkaz:
http://arxiv.org/abs/1604.06453
We use the averaged variational principle introduced in a recent article on graph spectra [7] to obtain upper bounds for sums of eigenvalues of several partial differential operators of interest in geometric analysis, which are analogues of Kr{\"o}ge
Externí odkaz:
http://arxiv.org/abs/1507.02632
Autor:
Colbois, Bruno, Soufi, Ahmad El
Publikováno v:
Mathematische Zeitschrift (2014) 1-18
We investigate properties of the sequences of extremal values that could be achieved by the eigenvalues of the Laplacian on Euclidean domains of unit volume, under Dirichlet and Neumann boundary conditions, respectively. In a second part, we study se
Externí odkaz:
http://arxiv.org/abs/1403.1993
Autor:
Soufi, Ahmad El, Harrell, Evans
We prove that among all doubly connected domains of $\R^n$ bounded by two spheres of given radii, $Z(t)$, the trace of the heat kernel with Dirichlet boundary conditions, achieves its minimum when the spheres are concentric (i.e., for the spherical s
Externí odkaz:
http://arxiv.org/abs/1402.3900
Publikováno v:
Communications in Analysis and Geometry (2014) 1-24
In this paper, we study the spectrum of the weighted Laplacian (also called Bakry-Emery or Witten Laplacian) $L_\sigma$ on a compact, connected, smooth Riemannian manifold $(M,g)$ endowed with a measure $\sigma dv_g$. First, we obtain upper bounds fo
Externí odkaz:
http://arxiv.org/abs/1310.1490
Autor:
Aribi, Amine, Soufi, Ahmad El
Publikováno v:
Calculus of Variations and Partial Differential Equations (2012) 1-27
We establish inequalities for the eigenvalues of the sub-Laplace operator associated with a pseudo-Hermitian structure on a strictly pseudoconvex CR manifold. Our inequalities extend those obtained by Niu and Zhang \cite{NiuZhang} for the Dirichlet e
Externí odkaz:
http://arxiv.org/abs/1301.6493
Publikováno v:
J. Funct. Anal. 261 (2011), no. 5, 1384-1399
Let N be a complete Riemannian manifold of dimension n+1 whose Riemannian metric g is conformally equivalent to a metric with non-negative Ricci curvature. The normalized Steklov eigenvalues of a bounded domain in N are bounded above in terms of the
Externí odkaz:
http://arxiv.org/abs/1103.2863