Funktionalkalküle für abgeschlossene lineare Operatoren in Banachräumen.
Gaussian estimates for Schrödinger perturbations
We propose a new general method of estimating Schrödinger perturbations of transition densities using an auxiliary transition density as a majorant of the perturbation series. We present applications to Gaussian bounds by proving an optimal inequality involving four Gaussian kernels, which we call the 4G Theorem. The applications come with honest control of constants in estimates of Schrödinger perturbations of Gaussian-type heat kernels and also allow for specific non-Kato perturbations.
General iterative algorithm for nonexpansive semigroups and variational inequalities in Hilbert spaces.
Generalized -almost periodic type functions in
In this paper, we analyze multi-dimensional quasi-asymptotically -almost periodic functions and their Stepanov generalizations as well as multi-dimensional Weyl -almost periodic type functions. We also analyze several important subclasses of the class of multi-dimensional quasi-asymptotically -almost periodic functions and reconsider the notion of semi--periodicity in the multi-dimensional setting, working in the general framework of Lebesgue spaces with variable exponent. We provide certain...
Generalized fractional linear transformations: convexity and compactness of the image and the pre-image; applications.
The convexity and compactness in the weak operator topology of the image and pre-image of a generalized fractional linear transformation is established. As an application the exponential dichotomy of solutions to evolution problems of the parabolic type is proved.
Generalized telegraph equation and the Sova-Kurtz version of the Trotter-Kato theorem
The Sova-Kurtz approximation theorem for semigroups is applied to prove convergence of solutions of the telegraph equation with small parameter. Convergence of the solutions of the diffusion equation with varying boundary conditions is also considered.
Generation of analytic semigroups by elliptic operators of second order in Hölder spaces
Generation of analytic semi-groups in L2 for a class of second order degenerate elliptic operators
Generators for quasi-free completely positive semi-groups
Generators of Brownian motions on abstract Wiener spaces
We prove that Brownian motion on an abstract Wiener space B generates a locally equicontinuous semigroup on equipped with the -topology introduced by L. Le Cam. Hence we obtain a “Laplace operator” as its infinitesimal generator. Using this Laplacian, we discuss Poisson’s equation and heat equation, and study its properties, especially the difference from the Gross Laplacian.
Global Existence and Boundedness of Solutions to a Model of Chemotaxis
A model of chemotaxis is analyzed that prevents blow-up of solutions. The model consists of a system of nonlinear partial differential equations for the spatial population density of a species and the spatial concentration of a chemoattractant in n-dimensional space. We prove the existence of solutions, which exist globally, and are L∞-bounded on finite time intervals. The hypotheses require nonlocal conditions on the species-induced production of the chemoattractant.
Global existence and nonexistence for semiliniear parabolic systems with nonlinear boundary conditions.
Global existence for a Riccati equation arising in a boundary control problem for distributed parameters
Si prova resistenza globale della soluzione di una equazione di Riccati collegata alla sintesi di un problema di controllo ottimale. Il problema considerato rappresenta la versione astratta di alcuni problemi governati da equazioni paraboliche con il controllo sulla frontiera.
Global Schauder estimates for a class of degenerate Kolmogorov equations
We consider a class of possibly degenerate second order elliptic operators on ℝⁿ. This class includes hypoelliptic Ornstein-Uhlenbeck type operators having an additional first order term with unbounded coefficients. We establish global Schauder estimates in Hölder spaces both for elliptic equations and for parabolic Cauchy problems involving . The Hölder spaces in question are defined with respect to a possibly non-Euclidean metric related to the operator . Schauder estimates are deduced by sharp...
Global solutions for a functional second order abstract Cauchy problem with nonlocal conditions
By using the theory of strongly continuous cosine families and the properties of completely continuous maps, we study the existence of mild, strong, classical and asymptotically almost periodic solutions for a functional second order abstract Cauchy problem with nonlocal conditions.
Global solutions for abstract functional differential equations with nonlocal conditions.
Global solutions of semilinear heat equations in Hilbert spaces.
Gradient estimates in parabolic problems with unbounded coefficients
We study, with purely analytic tools, existence, uniqueness and gradient estimates of the solutions to the Neumann problems associated with a second order elliptic operator with unbounded coefficients in spaces of continuous functions in an unbounded open set Ω in .
Group representations of bounded cosine functions.
Groups of Isometries on Certain Ideals of Hubert Space Operators.