Metric,Fractal Dimensional and Baire Results on the Distribution of Subsequences

Let X be a locally compact metric space. One important object connected with the distribution behavior of an arbitrary sequence x on X is the set M( x ) of limit measures of x . It is defined as the set of accumulation points of the sequence of the discrete measures induced by x . Using binary representation of reals one gets a natural bijective correspondence between infinite subsets of the set ℕ of positive integers and numbers in the unit interval I = 〈0, 1]. Hence to each sequence x = (x_n)_n∈ℕ ∈ X^ℕ and every a I there corresponds a subsequence denoted by a x . We investigate the set M(a x ) for given x with emphasis on the behavior for “typical” a in the sense of Baire category, Lebesgue measure and Hausdorff dimension.     

关于统计序列紧空间

在一般拓扑空间中,引入了序列紧空间的统计定义并讨论其相应的拓扑性质,深化了拓扑群与可度量化空间中关于序列紧空间的一些结果.     

On the predictability of discrete dynamical systems

Let be a metric space. A function is said to be non-sensitive at a point if for every 0$"> there is a 0$"> such that for any choice of points , , , we have that for every . Let be the set of all homeomorphisms from onto endowed with the topology of uniform convergence. The main goal of the present paper is to prove that for certain spaces , ``most' functions in are non-sensitive at ``most' points of .

     

On the convergence of and the Lip 1/2 class

We investigate the almost everywhere convergence of , where is a measurable function satisfying

By a known criterion, if satisfies the above conditions and belongs to the Lip class for some , then is a.e. convergent provided . Using probabilistic methods, we prove that the above result is best possible; in fact there exist Lip 1/2 functions and almost exponentially growing sequences such that is a.e. divergent for some with . For functions with Fourier series having a special structure, we also give necessary and sufficient convergence criteria. Finally we prove analogous results for the law of the iterated logarithm.

     

Statistically localized sequences in metric spaces

In this paper we have introduced the statistically localized sequences in metric spaces and investigate basic properties of the statistically localized sequences. Also we have obtained some necessary and sufficient conditions for a localized sequence to be a statistically Cauchy sequence. It is also defined uniformly statistically localized sequences on metric spaces and its relation with statistically Cauchy sequences has been investigated.     

φ^~混合随机变量列的几乎处处收敛性

本文研究(~φ)混合随机变量列的几乎处处收敛性,获得了(~φ)混合随机变量列的强大数律,推广和改进了独立情形的相应结果.     

On sets with Baire property in topological spaces

Steinhaus [9] prove that if a set A has a positive Lebesgue measure in the line then its distance set contains an interval. He obtained even stronger forms of this result in [9], which are concerned with mutual distances between points in an infinite sequence of sets. Similar theorems in the case we replace distance by mutual ratio were established by Bose-Majumdar [1]. In the present paper, we endeavour to obtain some results related to sets with Baire property in locally compact topological spaces, particular cases of which yield the Baire category analogues of the above results of Steinhaus [9] and their corresponding form for ratios by Bose-Majumdar [1].     

On Almost Unit-Regular Rings

An element a ∈ R is unit-regular provided that there exists an invertible u ∈ R such that a = aua. A ring R is called an almost unit-regular ring provided that for any a ∈ R, either a or 1 ? a is unit-regular. We characterize, in this article, the almost unit-regularity of Morita contexts with zero pairings. We also show that a ring R is unit-regular if and only if M ₂(R) is almost unit-regular. Various examples of such rings are constructed by means of formal triangular matrix rings.     

Quadratic functional equations in a set of Lebesgue measure zero

Let R$\mathbb{R}$ be the set of real numbers, Y   a Banach space and f:R→Y$f:\mathbb{R}\to Y$. We prove the Hyers–Ulam stability theorem for the quadratic functional inequality

‖f(x+y)+f(x−y)−2f(x)−2f(y)‖≤?$\Vert f(x+y)+f(x-y)-2f(x)-2f(y)\Vert \le ?$

for all (x,y)∈Ω$(x,y)\in \Omega$, where Ω⊂R²$\Omega \subset {\mathbb{R}}^2$ is of Lebesgue measure 0. Using the same method we dealt with the stability of two more functional equations in a set of Lebesgue measure 0.     

Statistically convergent difference double sequence spaces

In this article we define the notion of statistically convergent difference double sequence spaces. We examine the spaces 2l∞（△, q）, 2c（△, q）, 2cB（△, q）, 2cR（△, q）, 2cBR（△,q） etc. being symmetric, solid, monotone, etc. We prove some inclusion results too.     

Almost strongly regular matrices and a core theorem for double sequences

The idea of almost convergence for double sequences was introduced by Moricz and Rhoades [Math. Proc. Cambridge Philos. Soc. 104 (1988) 283-294] and they also characterized the four dimensional strong regular matrices. In this paper we define and characterize the almost strongly regular matrices for double sequences and apply these matrices to establish a core theorem.     

Almost sure convergence theorem and strong stability for weighted sums of NSD random variables

In this paper, Kolmogorov-type inequality for negatively superadditive dependent (NSD) random variables is established. By using this inequality, we obtain the almost sure convergence for NSD sequences, which extends the corresponding results for independent sequences and negatively associated (NA) sequences. In addition, the strong stability for weighted sums of NSD random variables is studied.     

Almost convergence and a core theorem for double sequences

The idea of almost convergence was introduced by Moricz and Rhoades [Math. Proc. Cambridge Philos. Soc. 104 (1988) 283-294] and they also characterized the four dimensional strong regular matrices. In this paper we define the M-core for double sequences and determine those four dimensional matrices which transform every bounded double sequence x=[x_jk] into one whose core is a subset of the M-core of x.     

On Almost Sure Convergence of Series of Random Variables Irrespective of Their Joint Distributions

In this article, necessary and sufficient conditions are presented for a series of random variables to converge absolutely almost surely irrespective of their joint distributions. The summands are not assumed to be integrable. Illustrative examples and counterexamples are presented.     

统计自相似集与随机不变测度

设犡是一完备可分度量空间，犓（ω）为Ｇｒａｆ随机模型下的随机递归集．该文构造了一列随机不变测度μ狀（狀≥１），它们是Ｈｕｔｃｈｉｎｓｏｎ确定模型下不变测度的推广；证明了存在一随机概率测度μ ，使得Ｓｕｐｐμ ＝犓（ω）且μ狀→μ （狀→∞）（弱收敛）；得到了μ狀的一些局部性质．     

On Regular Rings Satisfying Almost Comparability

In this article, we study regular rings satisfying almost comparability. We first show that, for regular rings, almost comparability is inherited by finitely generated projective modules and finite matrix rings, and, as a main result, we prove that the strict cancellation property holds for the family of all finitely generated projective modules over directly finite regular rings satisfying almost comparability.     

Large null sets in metric spaces

It is shown that every locally compact σ-compact metric space endowed with a Borel measure related to the metric by a natural condition contains sets of measure zero which are extremely large in the sense of cardinality, Hausdorff dimension and Baire category classification.     

正规几乎PP环

首先探讨正规几乎PP环的内刻划及左右对称性；其次，研究正规几乎PP环与PP环的关系，最后证明多项式环R［X」是正规几乎PP环当且仅当R是正规几乎PP环．