On a Kleinecke-Shirokov theorem
We prove that for normal operators the generalized commutator approaches zero when tends to zero in the norm of the Schatten-von Neumann class with and varies in a bounded set of such a class.
On a Li–Stević integral-type operators between different weighted Bloch-type spaces.
On a multiple Hilbert-type integral inequality with the symmetric kernel.
On a problem of Kadison and Singer.
On a property of Riesz spaces
On a question of Fremlin concerning order bounded and regular operators
On a Question of Pełczyński about Strictly Singular Operators
We exhibit new examples of weakly compact strictly singular operators with dual not strictly cosingular and characterize the weakly compact strictly singular surjections with strictly cosingular adjoint as those having strictly singular bitranspose. We then obtain new examples of super-strictly singular quotient maps and show that the strictly singular quotient maps in Kalton-Peck sequences are not super-strictly singular.
On a result of J. Johnson
On a similarity theory for rational Toeplitz operators.
On a singular integral
On a tensor product of weakly compact mappings
On a theorem of Gelfand and its local generalizations
In 1941, I. Gelfand proved that if a is a doubly power-bounded element of a Banach algebra A such that Sp(a) = 1, then a = 1. In [4], this result has been extended locally to a larger class of operators. In this note, we first give some quantitative local extensions of Gelfand-Hille’s results. Secondly, using the Bernstein inequality for multivariable functions, we give short and elementary proofs of two extensions of Gelfand’s theorem for m commuting bounded operators, , on a Banach space X.
On a theorem of H. P. Lotz on quasi-compactness of Markov operators
On a theorem of Jörgens and Chernoff concerning essential self-adjointness of Dirac operators.
On a theorem of Ky Fan
On a Theorem of Ky-Fan Type
On a theorem of L. Schwartz and its applications to absolutely summing operators
On a theorem of Stinespring concerning integral operators of trace class.
On a trace inequality for one-sided potentials and applications to the solvability of nonlinear integral equations.
On a weighted Toeplitz operator and its commutant.