O спектре операторов в идеальных пространствах
Obere Schranken für Eigenwerte von Eigenwertaufgaben der Form (...2 I Â?...A Â? B) x = 0 . - Upper Bounds for Eigenvalues of Quadratic Eigenvalue Problem.
Oka-analyticity of the essential spectrum
On a certain class of always convergent sequences and the Rayleigh quotient iterations
On a class of nonlinear eigenvalue problems
On a Class of Normaloid Operators.
On a class of operators
On a class of Toeplitz + Hankel operators.
On a Linear Operator Connected with Almost Periodic Solutions of a Linear Differential Equations in Banach Spaces
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 theorem of Lebow
On a theorem of Lebow and Mlak for several commuting operators
On an integral of fractional power operators
For a bounded and sectorial linear operator V in a Banach space, with spectrum in the open unit disc, we study the operator . We show, for example, that Ṽ is sectorial, and asymptotically of type 0. If V has single-point spectrum 0, then Ṽ is of type 0 with a single-point spectrum, and the operator I-Ṽ satisfies the Ritt resolvent condition. These results generalize an example of Lyubich, who studied the case where V is a classical Volterra operator.
On bare and semibare points for some classes of operators
On certain quantities in Fredholm operator theory and Mil'man's isometry spectrum
On complex interpolation and spectral continuity
Let , 0 ≤ t ≤ 1, be Banach spaces obtained via complex interpolation. With suitable hypotheses, linear operators T that act boundedly on both and will act boundedly on each . Let denote such an operator when considered on , and denote its spectrum. We are motivated by the question of whether or not the map is continuous on (0,1); this question remains open. In this paper, we study continuity of two related maps: (polynomially convex hull) and (boundary of the polynomially convex...
On continuity of linear transformations commuting with generalized scalar operators (Preliminary communication)
On coupling constant thresholds and related eigenvalue properties of Dirac operators.