Polar functions of multiparameter bifractional Brownian sheets

Let B^H,K ： （B^H,K（t）, t ∈R＋^N} be an （N,d）-bifractional Brownian sheet with Hurst indices H = （H1,..., HN） ∈ （0, 1）^N and K = （K1,..., KN）∈ （0, 1]^N. The characteristics of the polar functions for B^H,K are investigated. The relationship between the class of continuous functions satisfying the Lipschitz condition and the class of polar-functions of B^H,K is presented. The Hausdorff dimension of the fixed points and an inequality concerning the Kolmogorov＇s entropy index for B^H,K are obtained. A question proposed by LeGall about the existence of no-polar, continuous functions statisfying the Holder condition is also solved.     

N指标d维广义Brownian Sheet的像集及图集的Hausdorff测度

本文得到了Ｎ指标ｄ维广义Ｂｒｏｗｎｉａｎ Ｓｈｅｅｔ的像集及图集的Ｈａｕｓｄｏｒｆｆ测度的上、下界．     

广义统计自相似集的Hausdorff维数估计

作者进一步研究了在文章［１］中构造的广义统计自相似集的分形性质，得到了这类集合的Hausdorff维数和确切Hausdorff测度函数。文中的结果是［4］中结果的延拓。     

N指标d维广义Wiener过程的极性

本文讨论了N指标d维广义Wiener过程的极性,并得到了一个集合为极集的充分必要条件．     

分式Brown运动的极函数

设X(t)(t∈R^N)是指数为α的d维分式Brown运动。本文研究X（t）的极函数问题，得出了满足P｛t∈R^N\｛0｝，X（t）=f(t)=0｝的连续函数f组成的类的特征，解决了Legall提出的一个问题；并且得到了（N，N，2α）过程的不动点的Hausdorff维数。     

POLAR SETS OF MULTIPARAMETER BIFRACTIONAL BROWNIAN SHEETS

Let BH,K = {BH,K(t), t ∈ RN+ } be an (N, d)-bifractional Brownian sheet with Hurst indices H=(H1,···,HN) ∈(0,1)N and K=(K1,···,KN) ∈(0,1]N. The properties of the polar sets of BH,K are discussed. The sufficient conditions and necessary conditions for a compact set to be polar for BH,K are proved. The infimum of Hausdorff dimensions of its non-polar sets are obtained by means of constructing a Cantor-type set to connect its Hausdorff dimension and capacity.     

非退化扩散过程的水平集和极集

设X(t)(t∈R )是一个d维非退化扩散过程．本文得到了比原有结果更一般的非退化扩散过程极性的充分条件,证明了对任意u∈Rd,紧集E(0, ∞),有若d=1,则对任意紧集F(?)R, 若d≥2,则对任意紧集E ∈(0, ∞), 其中B(Rd)为Rd上的Borel σ-代数,dim和Dim分别表示Hausdorff维数和Packing 维数．     

广义布朗单的容度估计

研究了既没有平稳增量性,也没有scaling性质的N指标d维广义布朗单的容度问题．证明了广义布朗单“好象”一个局部平稳增量过程,应用Cairoli极大不等式和多参数鞅的方法得到了广义布朗单的碰撞概率与容度之间的关系,给出了其碰撞概率的确切容度估计．所得结果包含了布朗单和可加布朗运动的相应结果．     

DIMENSION OF POLAR SETS FOR BROWNIAN SHEET

Let W={W(t);t∈R_+~N} be the d-dimensional N-parameter Brownian Sheet. Sufficient conditions for a compact set F(?) Rd \ {0} to be a polar set for W are proved. It is also proved that if 2N ≤d, then for any compact set E (?) R_>~N ,     

一类广义齐次Moran集的Hausdorff维数

本文构造了一类具有类似高维Moran结构的集合,给出一些充分条件来计算其Hausdorff维数.     

Hausdorff and Packing Measures of the Level Sets of Iterated Brownian Motion

Burdzy and Khoshnevisan⁽⁹⁾ have shown that the Hausdorff dimension of the level sets of an iterated Brownian motion (IBM) is equal to 3/4. In this paper, the exact Hausdorff measure function and the packing measure of the levels set of IBM are given. Our approach relies on some accurate analysis on the local asymptotic of local times.     

Hitting probabilities and fractal dimensions of multiparameter multifractional Brownian motion

The main goal of this paper is to study the sample path properties for the harmonisable-type N-parameter multifractional Brownian motion, whose local regularities change as time evolves. We provide the upper and lower bounds on the hitting probabilities of an （N, d）-multifractional Brownian motion. Moreover, we determine the Hausdorff dimension of its inverse images, and the Hausdorff and packing dimensions of its level sets.     

稠密的s维分形集

对任意给定的0≤s≤1,本文构造Cantor型集E_s,使dim_H E_s=s,且E_s在[0,1]内稠密。     

N-d维广义Brownian单的像集一致Packing测度和一致Packing维数

我们获得了Ｎ－ｄ维广义Ｂｒｏｗｎｉａｎ单的像集的一致Ｐａｃｋｉｎｇ测度和一致Ｐａｃｋｉｎｇ维数。     

Julia集及其Hausdorff维数的连续性

对于d≥2,考虑多项式族Pc=Zd+c,c∈C.Kc={z∈C|{Pcn(z)}n≥0有界}为Pc的填充Julia集,Jc=(?)Kc为其Julia集.HD(Jc)为Jc的Hausdorff维数.设ω(0)为Pc0的临界点0的轨道的聚点集.我们假定Pc0在ω(0)上是扩张的,且O∈Jc0,|c0|>ε>0.如果一序列Cn→c0,则Jcn→Jc0,Kcn→Jc0,在Hausdorff拓扑下.如果存在一常数C1>0和一序列cn→c0,使得d(cn,Jc0)≥C1|cn-c0|1+1/d,则HD(Jcn)→HD(Jc0).这里d(cn,Jc0)为cn与Jc0间距离.     

Images of the Brownian sheet

An -parameter Brownian sheet in maps a non-random compact set in to the random compact set in . We prove two results on the image-set :

(1) It has positive -dimensional Lebesgue measure if and only if has positive -dimensional capacity. This generalizes greatly the earlier works of J. Hawkes  (1977), J.-P. Kahane  (1985), and Khoshnevisan (1999).

(2) If , then with probability one, we can find a finite number of points such that for any rotation matrix that leaves in , one of the 's is interior to . In particular, has interior-points a.s. This verifies a conjecture of T. S. Mountford  (1989).

This paper contains two novel ideas: To prove (1), we introduce and analyze a family of bridged sheets. Item (2) is proved by developing a notion of ``sectorial local-non-determinism (LND).' Both ideas may be of independent interest.

We showcase sectorial LND further by exhibiting some arithmetic properties of standard Brownian motion; this completes the work initiated by Mountford (1988).

     

广义递归集

对应于定义在一个由有限字符集Ｓ＝｛ａｉ｜１≤ｉ≤ｔ｝　所生成的自由半群Ｓ＊上的自同态映射θ，我们考虑Ｒｄ上的映射族（θ）＝｛Ｌ（ａｉ，ａｊ，ｋ，θ）｜１≤ｋ≤ｗ（ｉ，ｊ）｝　及同态映射ｆ：Ｓ　　满足在此框架上构造出广义递归集　　．此外当　为同态映射族时给出了其Ｈａｕｓｄｏｒｆｆ维数的上界估计；当　　为共形压缩映射族时确定了其Ｈａｕｓｄｏｒｆｆ维数.     

保形图递归集的Hausdorff维数和测度

本文确定了保形图递归集的 Ｈａｕｓｄｏｒｆｆ维数,证明了相应的 Ｈａｕｓｄｏｒｆｆ度是正σ－有限的,并且我们给出了 Ｈａｕｓｄｏｒｆｆ测度为正有限的充分必要条件．     

N指标d维广义Wiener过程象集的一个性质

设W（t）是N指标d维广义Winener过程,A↓Borel集W1,…,Em包含R^N,本文研究了W（t）象集的m项代数和W（E1）＋W（E2）＋…＋W（En）内点的存在性的问题。