Galerkin Method and Optimal Error Algorithms in Hilbert Spaces.
Gantmacher–Kreĭn theorem for 2 nonnegative operators in spaces of functions.
Gap and perturbation of non-semi-Fredholm operators.
Gâteaux derivative and orthogonality in -classes.
General numerical radius inequalities for matrices of operators
General Representation of Pseudoinverses
General results on the eigenvalues of operators with gaps, arising from both ends of the gaps. Application to Dirac operators
This paper is concerned with an extension and reinterpretation of previous results on the variational characterization of eigenvalues in gaps of the essential spectrum of self-adjoint operators. We state two general abstract results on the existence of eigenvalues in the gap and a continuation principle. Then these results are applied to Dirac operators in order to characterize simultaneously eigenvalues corresponding to electronic and positronic bound states.
Généralisation d'un théorème de Haagerup
Let G be a group of automorphisms of a tree X (with set of vertices S) and H a kernel on S × S invariant under the action of G. We want to give an estimate of the -operator norm (1 ≤ r ≤ 2) of the operator associated to H in terms of a norm for H. This was obtained by U. Haagerup when G is the free group acting simply transitively on a homogeneous tree. Our result is valid when X is a locally finite tree and one of the orbits of G is the set of vertices at even distance from a given vertex; a technical...
Generalisation of Rellich's Theorem on Perturbation of (Essentially) Selfadjoin Operators.
Generalization of formulae of Fredholm type
Generalization of von Neumann's spectral sets and integral representation of operators
Generalization of Weyl-von Neumann-Berg theorem for the case of normal operator-valued holomorphic functions
Generalizations of Cesàro means and poles of the resolvent
An improvement of the generalization-obtained in a previous article [Bu1] by the author-of the uniform ergodic theorem to poles of arbitrary order is derived. In order to answer two natural questions suggested by this result, two examples are also given. Namely, two bounded linear operators T and A are constructed such that converges uniformly to zero, the sum of the range and the kernel of 1-T being closed, and converges uniformly, the sum of the range of 1-A and the kernel of (1-A)² being...
Generalizations of Kaplansky's Theorem Involving Unbounded Linear Operators
We are mainly concerned with the result of Kaplansky on the composition of two normal operators in the case in which at least one of the operators is unbounded.
Generalizations of the Lax-Milgram theorem.
Generalizations of the results on powers of -hyponormal operators.
Generalized almost-convergence vs. matrix summability
Generalized a-Weyl's theorem and the single-valued extension property.
Let T be a bounded linear operator acting on a Banach space X such that T or T* has the single-valued extension property (SVEP). We prove that the spectral mapping theorem holds for the semi-essential approximate point spectrum σSBF-+(T); and we show that generalized a-Browder's theorem holds for f(T) for every analytic function f defined on an open neighbourhood U of σ(T): Moreover, we give a necessary and sufficient condition for such T to obey generalized a-Weyl's theorem. An application is given...
Generalized a-Weyl's theorem for direct sums
Generalized boundary value problems with abstract side conditions and their adjoints. II