Uniform Approximation of Entire Functions of Slow Growth on Compact Sets

In the present paper, we study the polynomial approximation of entire functions of several complex variables. The characterizations of generalized order and generalized type of entire functions of slow growth are obtained in terms of approximation and interpolation errors.     

亚纯函数微分多项式f~kQ[f]+P[f]的零点分布

从例外集的角度研究了亚纯函数微分多项式fkQ[f]+P[f]的零点分布,证明了:对于满足δ(∞,f)1-α>0的超越亚纯函数f(z),微分多项式fkQ[f]+P[f]在不含极点的可数个圆盘并集之外有无穷多个零点,其中k>1+ΓP+γP+α1(-1+αΓQ+ΓP-γP),ΓQ是Q[f]的权,ΓP,γP是P[f]的权和次数.本文推广了Hayman,Anderson,Langley等人的结论.     

On a generalization of Pólya’s theorem

We consider generalizations of Pólya’s theorem to the case of entire functions taking algebraic values at natural or integer points.     

The Hilbert problem: The case of infinitely many discontinuity points of coefficients

We obtain a solution to the Hilbert boundary value problem in the theory of analytic functions on the half-plane in the case that the coefficients of the boundary condition have countably many discontinuity points of the first kind. We elaborate the two substantially different situations: the series consisting of the jumps of the argument of the coefficient function and the increments of its continuous part converges and this series diverges. Accordingly, Hilbert problems with finite and infinite indices result. We derive formulas for the general solution and investigate the pictures of solvability of these problems.     

涉及微分多项式的亚纯函数的唯一性

设ｆ（ｚ）是非常数的整函数，ｎ是正整数，Ｆ（ｚ）＝ｆ￣（ｎ）（ｚ）＋ａ＿１（ｚ）ｆ￣（ｎ－１）（ｚ）＋…＋ａ＿ｎ（ｚ）ｆ（ｘ），其中ａ＿１（ｚ），ａ＿２（ｚ），…，ａ＿ｎ（ｚ）均是ｆ（ｚ）的小函数，本文证明了：若ｆ（ｚ）和Ｆ（ｚ）几乎ＣＭ分担两个不同的有穷复数ａ和ｂ，则ｆ（ｚ）≡Ｆ（ｚ）．     

一个微分方程的解及其应用

本文利用Gundersen的方法研究了一个线性微分方程的解并证明此方程的每一个整函数解的级必为无穷,推广了Gundersen和杨连中的若干结果。作为应用,我们还研究了与导数具有公共不动点的整函数.     

缺项幂级数的最小模与最大项(英文)

在本文中我们研究缺项幂级数的最小模与最大项间的关系，改进了Ｐ．Ｅｒｄｏｓ和Ａ．Ｊ．Ｍａｃｉｎｔｙｒｅ的结果     

ON THE GROWTH OF SOLUTIONS OF A CLASS OF HIGHER ORDER DIFFERENTIAL EQUATIONS

In this paper, authors investigate the order of growth and the hyper order of solutions of a class of the higher order linear differential equation, and improve results of M. Ozawa^[6], G. Gundersen^[7] and J.K. Langley^[8], Li Chun-hong^[11].     

Asymptotic Behavior of the Sum of the Dirichlet Series of Prescribed Growth on Curves

We study the relationship between the growth and decrease of the sum of the entire Dirichlet series of finite order (in the sense of Ritt) on arbitrary curves going to infinity. For a class of exponents having a regular distribution (in a certain sense), we obtain a test for the logarithm of the maximal term to be equivalent to the logarithm of the absolute value of the sum of the Dirichlet series on at least one unbounded sequence of points of the curve.__________Translated from Matematicheskie Zametki, vol. 78, no. 1, 2005, pp. 37–51.Original Russian Text Copyright © 2005 by A. M. Gaisin, I. D. Latypov.     

Estimates for the Involution of Decomposable Elements of a Complex Banach Algebra

An element a of a complex Banach algebra with unit \(1I\) and with standard conditions on the norm (‖ab‖ ⩽ ‖a‖ · ‖b‖ and ‖\(1I\)‖ = 1) is said to be Hermitian if ‖e ^ita ‖ = 1 for any real number t. An element is said to be decomposable if it admits a representation of the form a + ib in which a and b are Hermitian. The decomposable elements form a Banach Lie algebra (with respect to the commutator). The Hermitian components are determined uniquely, and hence this Lie algebra has the natural involution a + ib = x → x* = a − ib. One can readily see that ‖x*‖ ⩽ 2‖x‖. Among other things, we prove that ‖ x*‖ ⩽ γ‖x‖, where γ < 2. In fact, the situation is treated in more detail: the original problem is included in a continuous family parametrized by the numerical radius of the element. Finding the exact value of the constant γ is reduced to a variational problem in the theory of entire functions of exponential type. Approximately, γ is equal to 1.92 ± 0.04.