Carlemann Approximation on Riemann Surfaces.
Chebyshev approximation via polynomial mappings and the convergence behaviour of Krylov subspace methods.
Coincidence of some classes of universal functions.
Continuity properties of best analytic approximation.
Continuous symmetrized Sobolev inner products of order . II.
Convergence of rational interpolants.
Croissance et meilleure approximation polynomiale des fonctions entieres
Density of Polynomials in the L^2 Space on the Real and the Imaginary Axes and in a Sobolev Space
2000 Mathematics Subject Classification: 41A10, 30E10, 41A65.In this paper we consider an L^2 type space of scalar functions L^2 M, A (R u iR) which can be, in particular, the usual L^2 space of scalar functions on R u iR. We find conditions for density of polynomials in this space using a connection with the L^2 space of square-integrable matrix-valued functions on R with respect to a non-negative Hermitian matrix measure. The completness of L^2 M, A (R u iR ) is also established.
Derivative and antiderivative operators and the size of complex domains
We prove some conditions on a complex sequence for the existence of universal functions with respect to sequences of certain derivative and antiderivative operators related to it. These operators are defined on the space of holomorphic functions in a complex domain. Conditions for the equicontinuity of those sequences are also studied. The conditions depend upon the size of the domain.
Diagonal Padé approximants to hyperelliptic functions
Disjoint hypercyclic operators
We introduce the concept of disjoint hypercyclic operators. These are operators performing the approximation of any given vectors with a common subsequence of iterates applied on a common vector. The notion is extended to sequences of operators, and applied to composition operators and differential operators on spaces of analytic functions.
Effectiveness of transposed inverse sets in Faber regions.
Ein Approximationssatz für holomorphe Funktionen auf nicht-kompakte Riemannschen Flächen.
Ein funktionalanalytischer Beweis des Approximationssatzes von Walsh.
Eine Bemerkung zum Satz von Müntz.
Ensembles fermés polynomialement convexes
Entire functions with a given sequence of zeros and of regular behavior on the real axis. I.
Equiconvergence of some simultaneous Hermite-Padé interpolants
Estimates for capacities, and approximation in Lipschitz norms.
Exact asymptotics of nonlinear difference equations with levels and
We study a class of nonlinear difference equations admitting a -Gevrey formal power series solution which, in general, is not - (or Borel-) summable. Using right inverses of an associated difference operator on Banach spaces of so-called quasi-functions, we prove that this formal solution can be lifted to an analytic solution in a suitable domain of the complex plane and show that this analytic solution is an accelero-sum of the formal power series.