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Étude d'une fonction remarquable associée aux moyennes de convolution

Christian Even (1999)

Annales de l'institut Fourier

Dans cet article nous étudions la série génératrice des poids alternés d’une moyenne de convolution induite par un processus de diffusion. Nous montrons que celle-ci est une fonction méromorphe, naturellement liée à un certain opérateur compact. Cette fonction est simplement égale à d ( - z ) / d ( z ) , lorsque le déterminant de Fredholm d ( z ) de cet opérateur existe, et nous la précisons dans les autres cas.

Extended Weyl type theorems

M. Berkani, H. Zariouh (2009)

Mathematica Bohemica

An operator T acting on a Banach space X possesses property ( gw ) if σ a ( T ) σ SBF + - ( T ) = E ( T ) , where σ a ( T ) is the approximate point spectrum of T , σ SBF + - ( T ) is the essential semi-B-Fredholm spectrum of T and E ( T ) is the set of all isolated eigenvalues of T . In this paper we introduce and study two new properties ( b ) and ( gb ) in connection with Weyl type theorems, which are analogous respectively to Browder’s theorem and generalized Browder’s theorem. Among other, we prove that if T is a bounded linear operator acting on a Banach space X , then...

Extremal perturbations of semi-Fredholm operators

Thorsten Kröncke (1998)

Studia Mathematica

Let T be a bounded operator on an infinite-dimensional Banach space X and Ω a compact subset of the semi-Fredholm domain of T. We construct a finite rank perturbation F such that min[dim N(T+F-λ), codim R(T+F-λ)] = 0 for all λ ∈ Ω, and which is extremal in the sense that F² = 0 and rank F = max{min[dim N(T-λ), codim R(T-λ)] : λ ∈ Ω.

Fredholm determinants

Henry McKean (2011)

Open Mathematics

The article provides with a down to earth exposition of the Fredholm theory with applications to Brownian motion and KdV equation.

Fredholm spectrum and growth of cohomology groups

Jörg Eschmeier (2008)

Studia Mathematica

Let T ∈ L(E)ⁿ be a commuting tuple of bounded linear operators on a complex Banach space E and let σ F ( T ) = σ ( T ) σ e ( T ) be the non-essential spectrum of T. We show that, for each connected component M of the manifold R e g ( σ F ( T ) ) of all smooth points of σ F ( T ) , there is a number p ∈ 0, ..., n such that, for each point z ∈ M, the dimensions of the cohomology groups H p ( ( z - T ) k , E ) grow at least like the sequence ( k d ) k 1 with d = dim M.

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