On the differentiability of the norm in trace classes
N. Tomczak-Jaegermann (1974/1975)
Séminaire Analyse fonctionnelle (dit "Maurey-Schwartz")
N. de de Grande-de Kimpe (1975)
Journal für die reine und angewandte Mathematik
Etang Chen (1975)
Annales de l'I.H.P. Physique théorique
Hermann König (1981)
Colloquium Mathematicae
Hans Jarchow, Kamil John (1988)
Czechoslovak Mathematical Journal
Scherwentke, Przemysław (1995)
Portugaliae Mathematica
Ehrhard Behrends (1988)
Studia Mathematica
J.R. Holub (1973)
Mathematische Annalen
Joosep Lippus, Eve Oja (2007)
Studia Mathematica
Let X and Y be Banach spaces and let 𝓐(X,Y) be a closed subspace of 𝓛(X,Y), the Banach space of bounded linear operators from X to Y, containing the subspace 𝒦(X,Y) of compact operators. We prove that if Y has the metric compact approximation property and a certain geometric property M*(a,B,c), where a,c ≥ 0 and B is a compact set of scalars (Kalton's property (M*) = M*(1, {-1}, 1)), and if 𝓐(X,Y) ≠ 𝒦(X,Y), then there is no projection from 𝓐(X,Y) onto 𝒦(X,Y) with norm less than max|B| + c....
Giovanni Emmanuele (1997)
Commentationes Mathematicae Universitatis Carolinae
We show results about the existence and the nonexistence of a projection from the space of all linear and bounded operators from into onto the subspace of all representable operators.
Péter Battyányi (1996)
Commentationes Mathematicae Universitatis Carolinae
In this paper, we examine some questions concerned with certain ``skew'' properties of the range of a Jordan *-derivation. In the first part we deal with the question, for example, when the range of a Jordan *-derivation is a complex subspace. The second part of this note treats a problem in relation to the range of a generalized Jordan *-derivation.
Lajos Molnár (1994)
Commentationes Mathematicae Universitatis Carolinae
In this note, by means of the spectrum of the generating operator, we characterize the self-adjointness and closedness of the range of a normal and a self-adjoint Jordan *-derivation, respectively.
Marek Ptak (2007)
Banach Center Publications
A review of recent reflexivity and hyperreflexivity results is presented. We concentrate particularly on a finite-dimensional situation, Toeplitz operators and partial isometries. Open problems in this area are given.
Ptak Marek (1998)
Wojciech Młocek, Marek Ptak (2013)
Czechoslovak Mathematical Journal
The reflexivity and transitivity of subspaces of Toeplitz operators on the Hardy space on the upper half-plane are investigated. The dichotomic behavior (transitive or reflexive) of these subspaces is shown. It refers to the similar dichotomic behavior for subspaces of Toeplitz operators on the Hardy space on the unit disc. The isomorphism between the Hardy spaces on the unit disc and the upper half-plane is used. To keep weak* homeomorphism between spaces on the unit circle and the real line...
Yoshiaki Okazaki, Yashuii. Takahashi (1988)
Mathematische Annalen
Lawrence A. Harris (1977)
Monatshefte für Mathematik
Władysław A. Majewski, Marcin Marciniak (2007)
Banach Center Publications
The structure of the set of positive unital maps between M₂(ℂ) and Mₙ(ℂ) (n ≥ 3) is investigated. We proceed with the study of the "quantized" Choi matrix thus extending the methods of our previous paper [MM2]. In particular, we examine the quantized version of Størmer's extremality condition. Maps fulfilling this condition are characterized. To illustrate our approach, a careful analysis of Tang's maps is given.
Hellmut Baumgärtel (1984)
Annales de l'I.H.P. Physique théorique
Arora, S.C., Bala, Pawan (1992)
International Journal of Mathematics and Mathematical Sciences