An approximative solution of the generalized eigenvalue problem
An Atkinson-type theorem for B-Fredholm operators
Let X be a Banach space and let T be a bounded linear operator acting on X. Atkinson's well known theorem says that T is a Fredholm operator if and only if its projection in the algebra L(X)/F₀(X) is invertible, where F₀(X) is the ideal of finite rank operators in the algebra L(X) of bounded linear operators acting on X. In the main result of this paper we establish an Atkinson-type theorem for B-Fredholm operators. More precisely we prove that T is a B-Fredholm operator if and only if its projection...
An axiomatic approach to joint spectra I
An Elementary Lemma on Sequences of Integers and Its Apllications to Functional Analysis.
An embedding of the algebra of order bounded operators on a Dedekind complete Banach lattice.
An End Point Estimate for Maximal Commutators.
An equational approach to products of relatively regular operators.
An extension of the theory of Fredholm determinants
An improvement of Kaplansky's lemma on locally algebraic operators
An index formula for chains
We derive a formula for the index of Fredholm chains on normed spaces.
An index theorem for systems of difference operators on a half space
An individual ergodic theorem on the Hilbert space logic
An inequality for spherical Cauchy dual tuples
Let T be a spherical 2-expansive m-tuple and let denote its spherical Cauchy dual. If is commuting then the inequality holds for every positive integer k. In case m = 1, this reveals the rather curious fact that all positive integral powers of the Cauchy dual of a 2-expansive (or concave) operator are hyponormal.
An Inequality Involving a Hermitian Operator and its Square in a Normed Space
An infinite family of joint spectra
An Interpolation Result for the Spectral Radius.
An interpolation theorem with -weighted spaces
An introduction to Rota’s universal operators: properties, old and new examples and future issues
The Invariant Subspace Problem for Hilbert spaces is a long-standing question and the use of universal operators in the sense of Rota has been an important tool for studying such important problem. In this survey, we focus on Rota’s universal operators, pointing out their main properties and exhibiting some old and recent examples.
An irreducible semigroup of idempotents
We construct a semigroup of bounded idempotents with no nontrivial invariant closed subspace. This answers a question which was open for some time.
An Iteration Method for Studying the Bifurcation of Solutions of the Nonlinear Equations, L(...) u + ..R (..., u) = 0 .