On the Convergence and Approximation of Cosine Functions.
On the Cosine-Sine Operator Functional Equations
On the Cosine-Sine Operator Functional Equations (Short Communication)
On the differences of the consecutive powers of Banach algebra elements
Let A denote a complex unital Banach algebra. We characterize properties such as boundedness, relative compactness, and convergence of the sequence for an arbitrary x ∈ A, using σ(x) and resolvent conditions. Under these circumstances, we investigate elements in the peripheral spectrum, and give further conclusions, also involving the behaviour of and .
On the ellipticity and solvability of an abstract second-order differential equation.
On the Gelfand-Hille theorems
On the growth of analytic semigroups along vertical lines
We construct two Banach algebras, one which contains analytic semigroups such that arbitrarily slowly as , the other which contains ones such that arbitrarily fast
On the hypercontractivity property.
On the invertibility of isometric semigroup representations
Let T be a representation of a suitable abelian semigroup S by isometries on a Banach space. We study the spectral conditions which will imply that T(s) is invertible for each s in S. On the way we analyse the relationship between the spectrum of T, Sp(T,S), and its unitary spectrum . For or , we establish connections with polynomial convexity.
On the local ergodic theorems of Krengel, Kubokawa, and Terrell
On the modulus of one-parameter semigroups.
On the Perturbation Theory for Strongly Continuous Semigroups.
On the potential operators associated with a semigroup
On the quadratic optimal control problem for Volterra integro-differential equations
On the scattering theory for quantum dynamical semigroups
On the semigroup of mappings on Fréchet Montel space
On the Semigroup of the Stokes Operator for Exterior Domains in Lq-Spaces.
On the semigroups of age-size dependent population dynamcis with spatial diffusion.
On the Sharpness of Non-Optimal Approximation for Semigroup Operators.
On the solutions of the inhomogeneous evolution equation in Banach spaces
Vengono dati nuovi teoremi di regolarità per le soluzioni dell'equazione nel caso in cui è il generatore infinitesimale di un semigruppo analitico in uno spazio di Banach e è una funzione continua.