Approximation of eigenfunctions of elliptic differential operators

Monomiality Principle and Eigenfunctions of Differential Operators

LOCALIZATION OF EIGENFUNCTIONS OF ELLIPTIC OPERATORS (Research in teams)

Vibrations and waves play a major role in many fields of physics and of engineering, whether they are of acoustic, mechanical, optical or quantum nature. In many cases, the understanding of a vibrational system can be brought back to its spectral properties, i.e. the properties of the eigenvalues and eigenfunctions of the related wave operator. In disordered systems or in complex geometry, thes...

On the Spectral Properties of Degenerate Non-selfadjoint Elliptic systems of Differential Operators

some properties of fuzzy hilbert spaces and norm of operators

in this thesis, at first we investigate the bounded inverse theorem on fuzzy normed linear spaces and study the set of all compact operators on these spaces. then we introduce the notions of fuzzy boundedness and investigate a new norm operators and the relationship between continuity and boundedness. and, we show that the space of all fuzzy bounded operators is complete. finally, we define...

The spectral properties of differential operators with matrix coefficients on elliptic systems with boundary conditions

Let $$(Lv)(t)=sum^{n} _{i,j=1} (-1)^{j} d_{j} left( s^{2alpha}(t) b_{ij}(t) mu(t) d_{i}v(t)right),$$ be a non-selfadjoint differential operator on the Hilbert space $L_{2}(Omega)$ with Dirichlet-type boundary conditions. In continuing of papers [10-12], let the conditions made on the operator $ L$ be sufficiently more general than [11] and [12] as defined in Section $1$. In this paper, we estim...