On non-linear Volterra integral-functional equations in several variables
On nonlocal problems for ordinary differential equations and on a nonlocal parabolic transmission problem.
On nonnegative operators and fully cyclic peripheral spectrum.
On nonperturbative localization with quasi-periodic potential.
On non-quasidiagonal operators. II.
On nonstationary periodically correlated processes in complete correlated actions.
On nonunique fixed point theorems.
On non-zero dimensional atoms
On norm attaining operators acting from to C (S)
On norm attaining operators acting on - spaces
On norm closed ideals in
It is well known that the only proper non-trivial norm closed ideal in the algebra L(X) for (1 ≤ p < ∞) or X = c₀ is the ideal of compact operators. The next natural question is to describe all closed ideals of for 1 ≤ p,q < ∞, p ≠ q, or equivalently, the closed ideals in for p < q. This paper shows that for 1 < p < 2 < q < ∞ there are at least four distinct proper closed ideals in , including one that has not been studied before. The proofs use various methods from Banach...
On one class of matrix differential operators.
On one class of operators associated with differential equations of fractional order.
On one subset M. Schechter's essential spectrum
On operator bands
A multiplicative semigroup of idempotent operators is called an operator band. We prove that for each K>1 there exists an irreducible operator band on the Hilbert space which is norm-bounded by K. This implies that there exists an irreducible operator band on a Banach space such that each member has operator norm equal to 1. Given a positive integer r, we introduce a notion of weak r-transitivity of a set of bounded operators on a Banach space. We construct an operator band on that is weakly...
On operator ideals determined by sequences.
On operator valued solutions of d'Alembert's functional equation, II
On operators Cauchy dual to 2-hyperexpansive operators: the unbounded case
The Cauchy dual operator T’, given by , provides a bounded unitary invariant for a closed left-invertible T. Hence, in some special cases, problems in the theory of unbounded Hilbert space operators can be related to similar problems in the theory of bounded Hilbert space operators. In particular, for a closed expansive T with finite-dimensional cokernel, it is shown that T admits the Cowen-Douglas decomposition if and only if T’ admits the Wold-type decomposition (see Definitions 1.1 and 1.2 below)....
On operators close to isometries
We introduce and discuss a class of operators, to be referred to as operators close to isometries. The Bergman-type operators, 2-hyperexpansions, expansive p-isometries, and certain alternating hyperexpansions are main examples of such operators. We establish a few decomposition theorems for operators close to isometries. Applications are given to the theory of p-isometries and of hyperexpansive operators.
On operators factorizable through space