On completely invariant Fatou components

Completely invariant components of the Fatou sets of meromorphic maps are discussed. Positive answers are given to Baker’s and Bergweiler’s problems that such components are the only Fatou components for certain classes of meromorphic maps. Both authors are supported by NSFC and the 973 Project.     

Functions of small growth with no unbounded Fatou components

We prove a form of the cos πρ theorem which gives strong estimates for the minimum modulus of a transcendental entire function of order zero. We also prove a generalisation of a result of Hinkkanen that gives a sufficient condition for a transcendental entire function to have no unbounded Fatou components. These two results enable us to show that there is a large class of entire functions of order zero which have no unbounded Fatou components. On the other hand, we give examples which show that there are in fact functions of order zero which not only fail to satisfy Hinkkanen’s condition but also fail to satisfy our more general condition. We also give a new regularity condition that is sufficient to ensure that a transcendental entire function of order less than 1/2 has no unbounded Fatou components. Finally, we observe that all the conditions given here which guarantee that a transcendental entire function has no unbounded Fatou components also guarantee that the escaping set is connected, thus answering a question of Eremenko for such functions.     

An Isomorphic Version of Nakano’s Characterisation of <Emphasis Type="Italic">C</Emphasis><Subscript>0</Subscript>(Σ)

In 1941 Nakano gave a characterisation of real spaces C₀(Σ) as M-spaces satisfying an additional restriction on their norm. We give an isomorphic version of Nakano’s result which involves showing that for any Banach lattice (a suitably modified version of) Nakano’s condition is equivalent to the norm on the Dedekind completion being Fatou.     

Classification of invariant Fatou components for dissipative Hénon maps

Fatou components for rational endomorphisms of the Riemann sphere are fully classified and play an important role in our view of one-dimensional dynamics. In higher dimensions, the situation is less satisfactory. In this work we give a nearly complete classification of invariant Fatou components for moderately dissipative Hénon maps. Namely, we prove that any such a component is either an attracting or parabolic basin, or the basin of a rotation domain. More specifically, recurrent Fatou components were classified about 20 years ago (modulo the problem of existence of Herman ring basins), while in this paper we prove that non-recurrent invariant Fatou components are semi-parabolic basins. Most of our methods apply in a more general setting.     

A question of Eremenko and Lyubich concerning completely invariant domains and indirect singularities

We give an example of an entire function with a completely invariant Fatou component which has an indirect singularity not contained in this Fatou component. The question of whether such a function exists has been raised by Eremenko and Lyubich.

     

Tautness and Fatou Components in ?2

Hyperbolicity played an important role in the classification of Fatou components for rational functions in the Riemann sphere. In higher dimensions Fatou components are not nearly as well understood. We investigate the Kobayashi completeness and tautness of invariant Fatou components for holomorphic endomorphisms of ?² and for Hénon mappings. We show that basins of attraction and domains with an attracting Riemann surface, previously known to be taut, are also complete, which is strictly stronger. We also prove tautness for a class of Siegel domains.     

The Converse Fatou Theorem for Smooth Measures

We prove the converse of the Fatou theorem for small Zygmund measures defined on the Euclidean space. Bibliography: 5 titles. __________ Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 315, 2004, pp. 90–95.     

Ergodic Properties and Julia Sets of Weierstrass Elliptic Functions

 We discuss properties of the Julia and Fatou sets of Weierstrass elliptic ℘ functions arising from real lattices. We give sufficient conditions for the Julia sets to be the whole sphere and for the maps to be ergodic, exact, and conservative. We also give examples for which the Julia set is not the whole sphere.     

On locally solid topological lattice groups

Let (G, τ) be a commutative Hausdorff locally solid lattice group. In this paper we prove the following:

Ergodic Properties and Julia Sets of Weierstrass Elliptic Functions

 We discuss properties of the Julia and Fatou sets of Weierstrass elliptic ℘ functions arising from real lattices. We give sufficient conditions for the Julia sets to be the whole sphere and for the maps to be ergodic, exact, and conservative. We also give examples for which the Julia set is not the whole sphere. Received September 4, 2001; in revised form March 26, 2002     

On the structure of Fatou domains

Let U be a multiply-connected fixed attracting Fatou domain of a rational map f.We prove that there exist a rational map g and a completely invariant Fatou domain V of g such that(f,U) and(g,V) are holomorphically conjugate,and each non-trivial Julia component of g is a quasi-circle which bounds an eventually superattracting Fatou domain of g containing at most one postcritical point of g.Moreover,g is unique up to a holomorphic conjugation.     

超越整函数的某些动力学性质

本文研究了由m个超越整函数{fl,f2,…,fm}生成的随机迭代系统的Fatou集分支的某些动力学性质.运用复动力系统理论与双曲度量理论,得到了随机迭代系统有界Fatou分支不存在的一个判别准则,同时回答了Baker所提出的问题,且给出了随机迭代系统Fatou分支为单连通的一个充分条件,推广了Bergweiler的结果.     

A Fatou theorem for α-harmonic functions in Lipschitz domains

We study α-harmonic functions in Lipschitz domains. We prove a Fatou theorem when the boundary function is bounded and L^p-H?lder continuous of order β with βp > 1. Mathematics Subject Classifications (2000): Primary 31B25; Secondary 60J50 *Research supported by NSF Grant DMS0244737     

Gaps and Fatou theorems for series in Schauder basis of holomorphic functions

We prove a gap theorem and the “Fatou change-of-sign theorem” [Fatou, P., 1906, Sèries trigonométriques e séries de Taylor. Acta Mathematica, 39, 335–400] for expansions in common Schauder basis of holomorphic functions.     

An exact Fatou lemma for Gelfand integrals: a characterization of the Fatou property

We establish an exact version of Fatou’s lemma for Gelfand integrals of functions and multifunctions in dual Banach spaces without any order structure, and under the saturation property on the underlying measure space. The necessity and sufficiency of saturation for the Fatou property is demonstrated. Our result has a direct application to the equilibrium existence result for saturated economies without convexity assumptions.     

Periodic Fatou Components of Meromorphic Functions

In iteration theory of rational functions, it is well knownthat any Fatou component is mapped onto another in an n-to-1manner, and that periodic components are simply, doubly or infinitelyconnected. For meromorphic functions, the situation is much more complicated.Using Ahlfors' theory of covering surfaces, we prove that Fatoucomponents are mapped ‘nearly’ onto others, andthat periodic components are again simply, doubly or infinitelyconnected. Instead of considering meromorphic functions withonly one essential singularity, we allow countable sets of singularitiesand partly even sets of logarithmic capacity zero. It remains open whether doubly connected periodic componentsof meromorphic functions with only one singularity are necessarilyHerman rings (as holds for rational functions). However, thereis a function with two singularities and a doubly connectedperiodic component which is not an Herman ring. 1991 MathematicsSubject Classification 30D05, 30D30.     

斯泽古定理的历史研究

探讨幂级数在收敛圆上的行为表现是函数解析开拓的一个重要问题,"具有有限多个不同系数的幂级数"是其研究的重要一类,斯泽古定理即是该类级数研究的一个重要成果.文章基于原始文献,利用历史分析和比较的方法,探讨了斯泽古定理提出的思想背景,法都猜想是其重要的思想来源,详细分析了该定理的形成过程及进一步的发展,对深入理解斯泽古定理的发展历史具有重要作用.     

随机迭代系统的有界Fatou分支的存在性

本文研究了由m个超越整函数函数f1,f2,···,fm生成的随机迭代系统的Fatou分支的有界性问题.利用复动力系统理论的方法,得到一个Fatou连通分支U分别作为游荡域和非游荡域有界的条件,推广了Zheng的结果,同时也是对Baker的问题在随机迭代系统情形的一个回答.     

The resurgent character of the Fatou coordinates of a simple parabolic germ

Given a holomorphic germ at the origin of C$\mathbb{C}$ with a simple parabolic fixed point, the local dynamics is classically described by means of pairs of attracting and repelling Fatou coordinates and the corresponding pairs of horn maps, of crucial importance for Écalle-Voronin's classification result and the definition of the parabolic renormalization operator. We revisit Écalle's approach to the construction of Fatou coordinates, which relies on Borel–Laplace summation, and give an original and self-contained proof of their resurgent character.     

缺项幂级数表示的超越整函数Fatou分支有界性

讨论了几类用缺项幂级数表示的超越整函数Fatou集分支的有界性,并给出了其Fatou分支均有界的充分条件.