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Factorization of operators on C*-algebras

Narcisse Randrianantoanina (1998)

Studia Mathematica

Let A be a C*-algebra. We prove that every absolutely summing operator from A into 2 factors through a Hilbert space operator that belongs to the 4-Schatten-von Neumann class. We also provide finite-dimensional examples that show that one cannot replace the 4-Schatten-von Neumann class by the p-Schatten-von Neumann class for any p < 4. As an application, we show that there exists a modulus of capacity ε → N(ε) so that if A is a C*-algebra and T Π 1 ( A , 2 ) with π 1 ( T ) 1 , then for every ε >0, the ε-capacity of...

Factorization theorem for 1 -summing operators

Irene Ferrando (2011)

Czechoslovak Mathematical Journal

We study some classes of summing operators between spaces of integrable functions with respect to a vector measure in order to prove a factorization theorem for 1 -summing operators between Banach spaces.

Factorizing multilinear operators on Banach spaces, C*-algebras and JB*-triples

Carlos Palazuelos, Antonio M. Peralta, Ignacio Villanueva (2009)

Studia Mathematica

In recent papers, the Right and the Strong* topologies have been introduced and studied on general Banach spaces. We characterize different types of continuity for multilinear operators (joint, uniform, etc.) with respect to the above topologies. We also study the relations between them. Finally, in the last section, we relate the joint Strong*-to-norm continuity of a multilinear operator T defined on C*-algebras (respectively, JB*-triples) to C*-summability (respectively, JB*-triple-summability)....

Fourier analysis of a space of Hilbert-Shmidt operators. New Ha-plitz type operators.

Jaak Peetre (1990)

Publicacions Matemàtiques

If a group acts via unitary operators on a Hilbert space of functions then this group action extends in an obvious way to the space of Hilbert-Schmidt operators over the given Hilbert space. Even if the action on functions is irreducible, the action on H.-S. operators need not be irreducible. It is often of considerable interest to find out what the irreducible constituents are. Such an attitude has recently been advocated in the theory of "Ha-pliz" (Hankel + Toeplitz) operators. In this paper we...

Fourier analysis, Schur multipliers on S p and non-commutative Λ(p)-sets

Asma Harcharras (1999)

Studia Mathematica

This work deals with various questions concerning Fourier multipliers on L p , Schur multipliers on the Schatten class S p as well as their completely bounded versions when L p and S p are viewed as operator spaces. For this purpose we use subsets of ℤ enjoying the non-commutative Λ(p)-property which is a new analytic property much stronger than the classical Λ(p)-property. We start by studying the notion of non-commutative Λ(p)-sets in the general case of an arbitrary discrete group before turning to the...

Fuglede-Putnam theorem for class A operators

Salah Mecheri (2015)

Colloquium Mathematicae

Let A ∈ B(H) and B ∈ B(K). We say that A and B satisfy the Fuglede-Putnam theorem if AX = XB for some X ∈ B(K,H) implies A*X = XB*. Patel et al. (2006) showed that the Fuglede-Putnam theorem holds for class A(s,t) operators with s + t < 1 and they mentioned that the case s = t = 1 is still an open problem. In the present article we give a partial positive answer to this problem. We show that if A ∈ B(H) is a class A operator with reducing kernel and B* ∈ B(K) is a class 𝓨 operator, and AX =...

Fully summing mappings between Banach spaces

Mário C. Matos, Daniel M. Pellegrino (2007)

Studia Mathematica

We introduce and investigate the non-n-linear concept of fully summing mappings; if n = 1 this concept coincides with the notion of nonlinear absolutely summing mappings and in this sense this article unifies these two theories. We also introduce a non-n-linear definition of Hilbert-Schmidt mappings and sketch connections between this concept and fully summing mappings.

Generalized Derivations and Norm Equality in Normed Ideals

Barraa, Mohamed (2011)

Serdica Mathematical Journal

2000 Mathematics Subject Classification: 47A10, 47A12, 47A30, 47B10, 47B20, 47B37, 47B47, 47D50.We compare the norm of a generalized derivation on a Hilbert space with the norm of its restrictions to Schatten norm ideals.

Currently displaying 141 – 160 of 501