Schatten norms of Toeplitz matrices with Fisher--Hartwig singularities.
Sharpened Forms of an Inequality of Von Neumann.
Some Berezin number inequalities for operator matrices
Some Inequalities Associated with Certain Ordinary Differential Operators.
Some inequalities in .
Some Remarks on Inequalities of Landau and Kolmogorov.
Some remarks on the asymptotic behaviour of the iterates of a bounded linear operator
We discuss the problem of characterizing the possible asymptotic behaviour of the norm of the iterates of a bounded linear operator between two Banach spaces. In particular, given an increasing sequence of positive numbers tending to infinity, we construct Banach spaces such that the norm of the iterates of a suitable multiplication operator between these spaces assumes (or exceeds) the values of this sequence.
Some results about Beurling algebras with applications to operator theory
We prove that certain maximal ideals in Beurling algebras on the unit disc have approximate identities, and show the existence of functions with certain properties in these maximal ideals. We then use these results to prove that if T is a bounded operator on a Banach space X satisfying as n → ∞ for some β ≥ 0, then diverges for every x ∈ X such that .
Some variants of Anderson's inequality in -classes.
Some versions of Anderson's and Maher's inequalities. I.
Some versions of Anderson's and Maher's inequalities. II.
Some weighted sum and product inequalities in spaces and their applications.
Squaring a reverse AM-GM inequality
Let A, B be positive operators on a Hilbert space with 0 < m ≤ A, B ≤ M. Then for every unital positive linear map Φ, Φ²((A + B)/2) ≤ K²(h)Φ²(A ♯ B), and Φ²((A+B)/2) ≤ K²(h)(Φ(A) ♯ Φ(B))², where A ♯ B is the geometric mean and K(h) = (h+1)²/(4h) with h = M/m.
The complex Grothendieck inequality for 2x2 matrices
The critical exponent of operators with constrained spectral radius
The Polynomial-Normaloid Property for Banach-Space Operators
The pseudodifferential operator .
The strong unicity constant for projections.
Time regularity and functions of the Volterra operator
Our aim is to prove that for any fixed 1/2 < α < 1 there exists a Hilbert space contraction T such that σ(T) = 1 and . This answers Zemánek’s question on the time regularity property.
Transformation de Poisson sur un arbre localement fini
Dans cet article on étudie en premier lieu la résolvante (le noyau de Green) d’un opérateur agissant sur un arbre localement fini. Ce noyau est supposé invariant par un groupe d’automorphismes de l’arbre. On donne l’expression générique de cette résolvante et on établit des simplifications sous différentes hypothèses sur .En second lieu on introduit la transformation de Poisson qui associe à une mesure additive finie sur l’espace des bouts de l’arbre une fonction propre de l’ opérateur. On...