On a formula for the jumps in the semi-Fredholm domain.
In this paper we prove some properties of the lower s-numbers and derive asymptotic formulae for the jumps in the semi-Fredholm domain of a bounded linear operator on a Banach space.
On a general bidimensional extrapolation problem
Several generalized moment problems in two dimensions are particular cases of the general problem of giving conditions that ensure that two isometries, with domains and ranges contained in the same Hilbert space, have commutative unitary extensions to a space that contains the given one. Some results concerning this problem are presented and applied to the extension of functions of positive type.
On a generalization of Lumer-Phillips' theorem for dissipative operators in a Banach space
Using [1], which is a local generalization of Gelfand's result for powerbounded operators, we first give a quantitative local extension of Lumer-Philips' result that states conditions under which a quasi-nilpotent dissipative operator vanishes. Secondly, we also improve Lumer-Phillips' theorem on strongly continuous semigroups of contraction operators.
On a Hilbert-type integral inequality in the subinterval and its operator expression.
On a Hilbert-type operator with a symmetric homogeneous kernel of -order and applications.
On a Jensen-Mercer operator inequality.
On a Linear Operator Connected with Almost Periodic Solutions of a Linear Differential Equations in Banach Spaces
On a local ergodic theorem
On a maximum principle in potential theory
On a Method of Moments
On a nonstandard approach to invariant measures for Markov operators
We show the existence of invariant measures for Markov-Feller operators defined on completely regular topological spaces which satisfy the classical positivity condition.
On a problem concerning joint approximate point spectra
On a problem of moments of S. Rolewicz
On a property of weak resolvents and its application to a spectral problem
We show that the poles of a resolvent coincide with the poles of its weak resolvent up to their orders, for operators on Hilbert space which have some cyclic properties. Using this, we show that a theorem similar to the Mlak theorem holds under milder conditions, if a given operator and its adjoint have cyclic vectors.
On a question of Mbekhta.
The present paper deals with a question of M. Mbekhta concerning partial isometries on Banach spaces.
On a ratio ergodic theorem
On a reverse of Ando-Hiai inequality.
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 Ky-Fan Type