共查询到20条相似文献,搜索用时 46 毫秒
1.
YangChangsen 《高校应用数学学报(英文版)》2001,16(3):285-289
Abstract. Suppose H is a complex Hilbert space, AH (△) denotes the set of all analytic operator functions on 相似文献
2.
E. G. Goluzina 《Journal of Mathematical Sciences》2007,143(3):3023-3029
The paper studies the region of values Dm,n(T) of the system {f(z1), f(z2),..., f(zm), f(r1), f(r2),..., f(rn)}, where m ≥ 1; n > 1; zj, j = 1, ... m, are arbitrary fixed points of the disk U = {z: |z| < 1} with Im zj ≠ 0, j = 1, 2, ..., m; rj, 0 < rj < 1, j = 1, 2, ..., n, are fixed; f ∈ T, and the class T consists of functions f(z) = z + c2z2 + ... regular in the disk U and satisfying the condition Im f(z) · Im z > 0 for Im z ≠= 0, z ∈ U. An algebraic characterization of the set Dm,n(T) in terms of nonnegative-definite Hermitian forms is provided, and all the boundary functions are described. As an implication,
the region of values of f(z1) in the subclass of functions f ∈ T with prescribed values f(rj) (j = 1, 2, 3) is determined. Bibliography: 12 titles.
Dedicated to the 100th anniversary of my father’s birthday
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Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 337, 2006, pp. 23–34. 相似文献
3.
4.
E. G. Goluzina 《Journal of Mathematical Sciences》2008,150(3):2005-2012
The paper studies the regions of values of the systems {f(z1), f(r1), f(r2),…, f(rn)} and {f(r1), f(r2),…, f (rn)}, where n 2; z1 is an arbitrary fixed point of the disk U = {z: |z| < 1} with Im z1 ≠ 0; rj are fixed numbers, 0 < rj < 1, j = 1, 2,…, n; f ∈ T, and the class T consists of the functions f(z), f(0) = 0, f′(0) = 1, regular in the disk U and
satisfying the condition Im f(z) · Imz > 0 for Im z ≠ 0. As an implication, the region of values of f(z1) in the subclass of functions f ∈ T with prescribed values f(rj) (j = 1, 2,…, n) is determined. Bibliography: 12 titles.
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Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 350, 2007, pp. 5–16. 相似文献
5.
A. V. Harutyunyan W. Lusky 《Journal of Contemporary Mathematical Analysis (Armenian Academy of Sciences)》2010,45(3):128-135
Let U
n
be the unit polydisk in C
n
and S be the space of functions of regular variation. Let 1 ≤ p < ∞, ω = (ω
1, ..., ω
n
), ω
j
∈ S(1 ≤ j ≤ n) and f ∈ H(U
n
). The function f is said to be in holomorphic Besov space B
p
(ω) if
$
\left\| f \right\|_{B_p (\omega )}^p = \int_{U^n } {\left| {Df(z)} \right|^p \prod\limits_{j = 1}^n {\frac{{\omega _j (1 - |z_j |)}}
{{(1 - |z_j |^{2 - p} )}}} dm_{2n} (z) < + \infty }
$
\left\| f \right\|_{B_p (\omega )}^p = \int_{U^n } {\left| {Df(z)} \right|^p \prod\limits_{j = 1}^n {\frac{{\omega _j (1 - |z_j |)}}
{{(1 - |z_j |^{2 - p} )}}} dm_{2n} (z) < + \infty }
相似文献
6.
We study univalent holomorphic functions in the unit diskU = {z: |z| < 1} of the formf(z)=z+∑
n=2
∞
a
n
z
n
that satisfy the condition Re zf’(z)/f(z) > α with α∈ [0, 1) inU. Some integral means of such funcions are estimated. 相似文献
7.
In this paper we consider special elements of the Fock space #x2131;
n
. That is the space of entire functionsf:ℂ:
n
→ℂ, such that the followingL
2- condition is satisfied:
. Here we show that there exists an entire functiong:ℂ
n
→ℂ such that for every one-dimensional subspace Π⊂ℂ
n
and for all 0<∈<2 we have
, but in the limit case ∈=0 we have
. This result is analogue to a result from [1]. There holomorphic functions on the unit-ball are investigated. Furthermore
the proof — as the one in [1] — uses a theorem from [2]. Therefore we give another application of the results from [2] — namely
for spaces of entire functions. 相似文献
8.
LetH
∞ be the algebra of bounded analytic functions in the unit diskD. LetI=I(f
1,...,f
N) be the ideal generated byf
1,...,f
N∈H
∞ andJ=J(f
1,...,f
N) the ideal of the functionsf∈H
∞ for which there exists a constantC=C(f) such that |f(z)|≤C(|f
1
(z)|+...;+|f
N
(z)|),z∈D. It is clear that
, but an example due to J. Bourgain shows thatJ is not, in general, in the norm closure ofI. Our first result asserts thatJ is included in the norm closure ofI ifI contains a Carleson-Newman Blaschke product, or equivalently, if there existss>0 such that
9.
E. S. Dubtsov 《Journal of Mathematical Sciences》2007,141(5):1531-1537
Let
and τ denote the invariant gradient and invariant measure on the unit ball B of ℂn, respectively. Assume that f is a holomorphic function on B and ϕ ∈ C2(ℝ) is a nonnegative, nondecreasing, convex function. Then f belongs to the Hardy-Orlicz space H
ϕ(B>) if and only if
10.
Joaquim Ortega-Cerdà 《Arkiv f?r Matematik》1998,36(1):103-117
We characterize in geometric terms the zero sets of holomorphic functionsf in the bidisk such that log |f|∈L
p
(D
2) for 1<p<∞.
Partially supported by the DGCYT grant PB95-0956-C02-02 and grant 1996-SGR-26. 相似文献
11.
Countably generated prime ideals in <Emphasis Type="Italic">H</Emphasis><Superscript>∞</Superscript>
We confirm a twenty year old conjecture by showing that a nonzero prime ideal P in the algebra H∞ of bounded analytic functions in the open unit disk is countably generated if and only if it is either a principal ideal
generated by the polynomial z−z0, |z0|<1, or if P is generated by the n-th roots of an atomic inner function. The case of the algebra H∞+C is also dealt with.
Dedicated to the 70th birthday of Joseph Cima
Research supported by the RIP-program Oberwolfach 2004. 相似文献
12.
V. V. Savchuk 《Ukrainian Mathematical Journal》2007,59(8):1163-1183
We establish necessary and sufficient conditions under which a real-valued function from
, 1 ≤ p < ∞, is badly approximable by the Hardy subspace H
p
0
:= {ƒ ∈ H
p
: ƒ(0) = 0}. In a number of cases, we obtain the exact values of the best approximations in the mean of functions holomorphic
in the unit disk by functions holomorphic outside this disk. We use the obtained results for finding the exact values of the
best polynomial approximations and n-widths of some classes of holomorphic functions. We establish necessary and sufficient conditions under which the generalized
Bernstein inequality for algebraic polynomials on the unit circle is true.
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Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 59, No. 8, pp. 1047–1067, August, 2007. 相似文献
13.
Piotr Kot 《Czechoslovak Mathematical Journal》2009,59(2):371-379
We solve the following Dirichlet problem on the bounded balanced domain with some additional properties: For p > 0 and a positive lower semi-continuous function u on ∂Ω with u(z) = u(λ z) for |λ| = 1, z ∈ ∂Ω we construct a holomorphic function f ∈ (Ω) such that for z ∈ ∂Ω, where = {λ ∈ ℂ: |λ| < 1}.
相似文献
14.
K. -J. Wirths 《Constructive Approximation》1999,15(3):427-440
In this paper we construct Bloch functions F for which the set {z | e sup
|ζ| < 1
|F'(ζ)| ( 1 - |ζ|
2
) = |F'(z)| ( 1 - |z|
2
)} is an analytic Jordan curve tangential to the unit disk in some points. It is proved that, using such functions, we can
derive analogs to the Taylor expansion for Bloch functions in cases where the Taylor expansion does not converge.
October 15, 1997. Date revised: March 12, 1998. Date accepted: June 18, 1998. 相似文献
15.
Cristina Trombetti 《Annali di Matematica Pura ed Applicata》1999,177(1):277-292
Summary We prove the existence of minimizing pairs (K, u), K compact set ofR
N and u∈W1, p (Ω/K), for the functional
when the integrand f(x, z) is convex with respect to z, |z|p≤f(x, z)≤L|z|p, p>1, and satisfies suitable assumptions of uniform continuity in x with respect to z.
Entrata in Redazione il 10 luglio 1998. 相似文献
16.
In this paper, we obtain a version of subordination lemma for hyperbolic disk relative to hyperbolic geometry on the unit disk D. This subordination lemma yields the distortion theorem for Bloch mappings f ∈ H(B^n) satisfying ||f||0 = 1 and det f'(0) = α ∈ (0, 1], where||f||0 = sup{(1 - |z|^2 )n+1/2n det(f'(z))[1/n : z ∈ B^n}. Here we establish the distortion theorem from a unified perspective and generalize some known results. This distortion theorem enables us to obtain a lower bound for the radius of the largest univalent ball in the image of f centered at f(0). When a = 1, the lower bound reduces to that of Bloch constant found by Liu. When n = 1, our distortion theorem coincides with that of Bonk, Minda and Yanagihara. 相似文献
17.
A. Yu. Solynin 《Journal of Mathematical Sciences》1996,79(5):1341-1358
We consider the class S1(τ), 0<τ<1, of functions f(z)=rz+a2z2+... that are regular and univalent in the unit disk U and have |f(z)|<1. We obtain sharp estimates for the 1-measure of the
sets {θ: |f(eiθ)|=1}. As a corollary, for the familiar class S we find Kolmogorov-type estimates for the sets {θ: |f(eiθ)|>M}, M>1, and prove inequalities for the harmonic measure, which are similar to those by Carleman-Milloux and Baernstein.
We also consider problems on distortion of fixed systems of boundary arcs in the classes of functions that are regular (or
meromorphic) and univalent in the disk or circular annulus. Bibliography: 23 titles.
Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 204, 1993, pp. 115–142.
Translated by A. Yu. solynin. 相似文献
18.
19.
LiJunjie BianBaojun 《高校应用数学学报(英文版)》2000,15(3):273-280
The following regularity of weak solutions of a class of elliptic equations of the form are investigated. 相似文献
20.
D. V. Prokhorov 《Mathematical Notes》1997,61(5):609-613
We solve the maximal value problem for the functional
in the class of functionsf(z)=z+a
2z2+… that are holomorphic and univalent in the unit disk and satisfy the inequality |f(z)|<M. We prove that the Pick functions are extremal for this problem for sufficiently largeM whenever the set of indicesk
1,…,km contains an even number.
Translated fromMatematicheskie Zametki, Vol. 61, No. 5, pp. 728–733, May, 1997.
Translated by S. S. Anisov 相似文献
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