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On the value distribution of differential polynomials of meromorphic functions

Yan Xu, Huiling Qiu (2010)

Annales Polonici Mathematici

Let f be a transcendental meromorphic function of infinite order on ℂ, let k ∈ ℕ and φ = R e P , where R ≢ 0 is a rational function and P is a polynomial, and let a , a , . . . , a k - 1 be holomorphic functions on ℂ. If all zeros of f have multiplicity at least k except possibly finitely many, and f = 0 f ( k ) + a k - 1 f ( k - 1 ) + + a f = 0 , then f ( k ) + a k - 1 f ( k - 1 ) + + a f - φ has infinitely many zeros.

Polynômes de Lagrange sur les entiers d'un corps quadratique imaginaire

M. Ably, M. M'Zari (1998)

Journal de théorie des nombres de Bordeaux

L'objet de ce texte est de donner une estimation arithmétique des valeurs prises par les polynômes de Lagrange sur les entiers d'un corps quadratique imaginaire en des points de ce corps. Ces polynômes interviennent dans l'étude des fonctions entières arithmétiques et dans les minorations de formes linéaires de Logarithmes.

Power-bounded elements and radical Banach algebras

Graham Allan (1997)

Banach Center Publications

Firstly, we give extensions of results of Gelfand, Esterle and Katznelson--Tzafriri on power-bounded operators. Secondly, some results and questions relating to power-bounded elements in the unitization of a commutative radical Banach algebra are discussed.

Problems and Theorems in the Theory of Multiplier Sequences

Craven, Thomas, Csordas, George (1996)

Serdica Mathematical Journal

The purpose of this paper is (1) to highlight some recent and heretofore unpublished results in the theory of multiplier sequences and (2) to survey some open problems in this area of research. For the sake of clarity of exposition, we have grouped the problems in three subsections, although several of the problems are interrelated. For the reader’s convenience, we have included the pertinent definitions, cited references and related results, and in several instances, elucidated the problems by...

Some Coefficient Estimates for Polynomials on the Unit Interval

Qazi, M. A., Rahman, Q. I. (2007)

Serdica Mathematical Journal

2000 Mathematics Subject Classification: 26C05, 26C10, 30A12, 30D15, 42A05, 42C05.In this paper we present some inequalities about the moduli of the coefficients of polynomials of the form f (x) : = еn = 0nan xn, where a0, ј, an О C. They can be seen as generalizations, refinements or analogues of the famous inequality of P. L. Chebyshev, according to which |an| Ј 2n-1 if | еn = 0n an xn | Ј 1 for -1 Ј x Ј 1.

Spaces of sequences, sampling theorem, and functions of exponential type

Rodolfo Torres (1991)

Studia Mathematica

We introduce certain spaces of sequences which can be used to characterize spaces of functions of exponential type. We present a generalized version of the sampling theorem and a "nonorthogonal wavelet decomposition" for the elements of these spaces of sequences. In particular, we obtain a discrete version of the so-called φ-transform studied in [6] [8]. We also show how these new spaces and the corresponding decompositions can be used to study multiplier operators on Besov spaces.

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