AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimensional separable Hilbert space H⊕K of the form MC=(AC0B). In this paper, we prove that⋂C∈B(K,H)σb(MC)=σab(A)∪σab(B∗)∪{λ∈C:n(A−λI)+n(B−λI)≠d(A−λI)+d(B−λI)}, where σb(T), σab(T), n(T), d(T) and T∗ denote the Browder spectrum, Browder essential approximate point spectrum, nullity, deficiency and conjugate of T, respectively. Some related results are obtained
AbstractIn this paper we investigate perturbations of the regular spectrum of an upper triangular op...
We relate the ascent and descent of n-tuples of multiplication operators Ma,b(u)=aub to that of the ...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the Hilbert space H...
AbstractLet σab(T)={λ∈C:T-λIisnotanuppersemi-Fredholmoperatorwithfiniteascent} be the Browder essent...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator matrix acting on the infinite...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite-dimens...
AbstractFor A∈B(X), B∈B(Y) and C∈B(Y,X), let MC be the operator defined on X⊕Y by [AC0B]. In this pa...
AbstractLet MC denote a 2×2 upper triangular operator matrix of the form MC=AC0B, which is acting on...
AbstractWe consider upper-triangular 2-by-2 operator matrices and are interested in the set that has...
AbstractLet B(H) denote the algebra of operators on an infinite dimensional complex Hilbert space H,...
In this paper, we study the unbounded upper triangular operator matrix with diagonal domain. Some su...
AbstractIn this paper we investigate perturbations of the regular spectrum of an upper triangular op...
We relate the ascent and descent of n-tuples of multiplication operators Ma,b(u)=aub to that of the ...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the Hilbert space H...
AbstractLet σab(T)={λ∈C:T-λIisnotanuppersemi-Fredholmoperatorwithfiniteascent} be the Browder essent...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator matrix acting on the infinite...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite-dimens...
AbstractFor A∈B(X), B∈B(Y) and C∈B(Y,X), let MC be the operator defined on X⊕Y by [AC0B]. In this pa...
AbstractLet MC denote a 2×2 upper triangular operator matrix of the form MC=AC0B, which is acting on...
AbstractWe consider upper-triangular 2-by-2 operator matrices and are interested in the set that has...
AbstractLet B(H) denote the algebra of operators on an infinite dimensional complex Hilbert space H,...
In this paper, we study the unbounded upper triangular operator matrix with diagonal domain. Some su...
AbstractIn this paper we investigate perturbations of the regular spectrum of an upper triangular op...
We relate the ascent and descent of n-tuples of multiplication operators Ma,b(u)=aub to that of the ...
AbstractWhen A∈B(H) and B∈B(K) are given, we denote by MC the operator acting on the infinite dimens...
DOI
Add to ORKG