-convexity and best approximation.
-ideals of compact operators into
We show for and subspaces of quotients of with a -unconditional finite-dimensional Schauder decomposition that is an -ideal in .
M - Paranormal Operators
-ideals of compact operators
We study the position of compact operators in the space of all continuous linear operators and its subspaces in terms of ideals. One of our main results states that for Banach spaces and the subspace of all compact operators is an -ideal in the space of all continuous linear operators whenever and are - and -ideals in and , respectively, with and . We also prove that the -ideal in is separably determined. Among others, our results complete and improve some well-known results...
Majoration de multiplicité pour l'opérateur de Schrödinger
Majoration des semi-groupes de contractions de L1 et applications
Majoration du nombre de résonances près de l'axe réel (d'après un travail avec M. Zworski)
Majorization of -semigroups in ordered Banach spaces
We give criteria for domination of strongly continuous semigroups in ordered Banach spaces that are not necessarily lattices, and thus obtain generalizations of certain results known in the lattice case. We give applications to semigroups generated by differential operators in function spaces which are not lattices.
Majorizations for Generalized s-Numbers in Semifinite von Neumann Algebras.
Mann iterates of directionally nonexpansive mappings in hyperbolic spaces.
Mann iteration converges faster than Ishikawa iteration for the class of Zamfirescu operators.
Mann type implicit iteration approximation for multivalued mappings in Banach spaces.
Mapping properties of maximal operators
Mappings into spaces of operators
Mappings of monotone type: Theory and applications
Mappings of positive integers and subspaces of m
Mappings on some reflexive algebras characterized by action on zero products or Jordan zero products
Let 𝓛 be a subspace lattice on a Banach space X and let δ: Alg𝓛 → B(X) be a linear mapping. If ⋁ {L ∈ 𝓛 : L₋ ⊉ L}= X or ⋁ {L₋ : L ∈ 𝓛, L₋ ⊉ L} = (0), we show that the following three conditions are equivalent: (1) δ(AB) = δ(A)B + Aδ(B) whenever AB = 0; (2) δ(AB + BA) = δ(A)B + Aδ(B) + δ(B)A + Bδ(A) whenever AB + BA = 0; (3) δ is a generalized derivation and δ(I) ∈ (Alg𝓛)'. If ⋁ {L ∈ 𝓛 : L₋ ⊉ L} = X or ⋁ {L₋ : L ∈ 𝓛, L₋ ⊉ L} = (0) and δ satisfies δ(AB + BA) = δ(A)B + Aδ(B) + δ(B)A + Bδ(A)...
Mappings preserving zero products
Let θ : ℳ → 𝓝 be a zero-product preserving linear map between algebras. We show that under some mild conditions θ is a product of a central element and an algebra homomorphism. Our result applies to matrix algebras, standard operator algebras, C*-algebras and W*-algebras.
Maps between Banach function algebras satisfying certain norm conditions
Let A and B be Banach function algebras on compact Hausdorff spaces X and Y, respectively, and let and be their uniform closures. Let I, I′ be arbitrary non-empty sets, α ∈ ℂ{0, ρ: I → A, τ: l′ → a and S: I → B T: l′ → B be maps such that ρ(I, τ(I′) and S(I), T(I′) are closed under multiplications and contain exp A and expB, respectively. We show that if ‖S(p)T(p′)−α‖Y=‖ρ(p)τ(p′) − α‖x for all p ∈ I and p′ ∈ I′, then there exist a real algebra isomorphism S: A → B, a clopen subset K of M B and...
Maps on idempotent operators
The set of all bounded linear idempotent operators on a Banach space X is a poset with the partial order defined by P ≤ Q if PQ = QP = P. Another natural relation on the set of idempotent operators is the orthogonality relation defined by P ⊥ Q ⇔ PQ = QP = 0. We briefly survey known theorems on maps on idempotents preserving order or orthogonality. We discuss some related results and open problems. The connections with physics, geometry, theory of automorphisms, and linear preserver problems will...