The linear modulus of an integral operator
The linear symmetric systems associated with the modified Cherednik operators and applications
We introduce and study the linear symmetric systems associated with the modified Cherednik operators. We prove the well-posedness results for the Cauchy problem for these systems. Eventually we describe the finite propagation speed property of it.
The mappings of degree 1.
The maximal normal subspace of the inverse image of a normal space of sequences by a non-negative matrix transformation
The moduli of smoothness and convexity and the Rademacher averages of the trace classes (1≤p<∞)
The Modulus of a Weakly Compact Operator.
The multiplication functions of Kučera
The norms and singular numbers of polynomials of the classical Volterra operator in L₂(0,1)
The spectral problem (s²I - ϕ(V)*ϕ(V))f = 0 for an arbitrary complex polynomial ϕ of the classical Volterra operator V in L₂(0,1) is considered. An equivalent boundary value problem for a differential equation of order 2n, n = deg(ϕ), is constructed. In the case ϕ(z) = 1 + az the singular numbers are explicitly described in terms of roots of a transcendental equation, their localization and asymptotic behavior is investigated, and an explicit formula for the ||I + aV||₂ is given. For all a ≠ 0 this...
The numerical radius of a weighted shift operator with geometric weights.
The numerical range of Toeplitz operator on the polydisk.
The one-sided ergodic Hilbert transform in Banach spaces
Let T be a power-bounded operator on a (real or complex) Banach space. We study the convergence of the one-sided ergodic Hilbert transform . We prove that weak and strong convergence are equivalent, and in a reflexive space also is equivalent to the convergence. We also show that (which converges on (I-T)X) is precisely the infinitesimal generator of the semigroup .
The only continuous Volterra right inverses in of the operator are
The order -complete vector lattice of AM-compact operators
We establish necessary and sufficient conditions under which the linear span of positive AM-compact operators (in the sense of Fremlin) from a Banach lattice into a Banach lattice is an order -complete vector lattice.
The Ornstein-Uhlenbeck generator perturbed by the gradient of a potential
Si considera, in uno spazio di Hilbert l'operatore lineare , dove è un operatore negative autoaggiunto e è un potenziale che soddisfa a opportune condizioni di integrabilità. Si dimostra con un metodo analitico che è essenzialmente autoaggiunto in uno spazio e si caratterizza il dominio della sua chiusura come sottospazio di . Si studia inoltre la «spectral gap property» del semigruppo generato da .
The partial-isometric crossed products of by the forward and backward shifts.
The Peripheral Point Spectrum of Schwarz Operators on C*-Algebras.
The Perron-Frobenius theorem in relative spectral theory.
The Pick problem and the Cole-Lewis-Wermer theorem.
The Pick problem in and and the Cole-Lewis-Wermer problem.
The Polynomial-Normaloid Property for Banach-Space Operators