Théorie spectrale d'une classe d'opérateurs elliptiques dégénérés non nécessairement auto-adjoint
Time decay estimates for a perturbed wave equation
Two lectures on spectral invariants for the Schrödinger operator
Two separation criteria for second order ordinary or partial differential operators
We generalize a well-known separation condition of Everitt and Giertz to a class of weighted symmetric partial differential operators defined on domains in . Also, for symmetric second-order ordinary differential operators we show that where is a singular point guarantees separation of on its minimal domain and extend this criterion to the partial differential setting. As a particular example it is shown that is separated on its minimal domain if is superharmonic. For the criterion...
Über das Spektrum des Laplace-Operators in einigen unbeschränkten Gebieten.
Über Regularitätseigenschaften der Potenzräume eines Schrödinger-Operators mit singulärem Potential.
Über Verallgemeinerungen des Virialsatzes und Existenzfragen von Eigenwerten bei Schrödingeroperatoren
Une inégalité universelle pour la première valeur propre du laplacien
Unique continuation property near a corner and its fluid-structure controllability consequences
We study a non standard unique continuation property for the biharmonic spectral problem in a 2D corner with homogeneous Dirichlet boundary conditions and a supplementary third order boundary condition on one side of the corner. We prove that if the corner has an angle , and , a unique continuation property holds. Approximate controllability of a 2-D linear fluid-structure problem follows from this property, with a control acting on the elastic side of a corner in a domain containing a Stokes...
Unique continuation property near a corner and its fluid-structure controllability consequences
We study a non standard unique continuation property for the biharmonic spectral problem in a 2D corner with homogeneous Dirichlet boundary conditions and a supplementary third order boundary condition on one side of the corner. We prove that if the corner has an angle , and , a unique continuation property holds. Approximate controllability of a 2-D linear fluid-structure problem follows from this property, with a control acting on the elastic side of a corner in a domain containing...
Vacuum energy as spectral geometry.
Valeurs propres d'une classe d'équations différentielles singulières sur une demi-droite
Variational characterization of eigenvalues of a non-symmetric eigenvalue problem governing elastoacoustic vibrations
Small amplitude vibrations of an elastic structure completely filled by a fluid are considered. Describing the structure by displacements and the fluid by its pressure field one arrives at a non-selfadjoint eigenvalue problem. Taking advantage of a Rayleigh functional we prove that its eigenvalues can be characterized by variational principles of Rayleigh, minmax and maxmin type.
Weak Bloch property and weight estimates for elliptic operators
Weak solutions for the -Laplacian with a nonlinear boundary condition at resonance.
Wegner estimates and Anderson localization for alloy-type potentials.
Weighted norm estimates and -spectral independence of linear operators
We investigate the -spectrum of linear operators defined consistently on for p₀ ≤ p ≤ p₁, where (Ω,μ) is an arbitrary σ-finite measure space and 1 ≤ p₀ < p₁ ≤ ∞. We prove p-independence of the -spectrum assuming weighted norm estimates. The assumptions are formulated in terms of a measurable semi-metric d on (Ω,μ); the balls with respect to this semi-metric are required to satisfy a subexponential volume growth condition. We show how previous results on -spectral independence can be treated...
Zur Abschätzung der Spektralfunktion elliptischer Operatoren.
Zur Existenz des Wellenoperators bei Anfangsrandwertproblemen vom Maxwell-Typ.
Асимптотика плотности состояний гипоэллиптических почти-периодических операторов