Approximate duality of g-frames in Hilbert spaces

In this article, we introduce and characterize approximate duality for g-frames. We get some important properties and applications of approximate duals. We also obtain some new results in approximate duality of frames, and generalize some of the known results in approximate duality of frames to g-frames. We also get some results for fusion frames, and perturbation of approximately dual g-frames. We show that approximate duals are stable under small perturbations and they are useful for erasures and reconstruction.     

一类单位逼近所定义的卷积函数的边界分形性质

我们研究一类单位逼近与具有重分形分解的测度的卷积所定义的函数，给出测度的局部Ｌｉｐｓｃｈｉｔｚ指数与函数的奇异边界增长性质的关系．特别应用于Ｐｏｉｓｏｎ核和Ｇａｕｓ Ｗｅｉｅｒｓｔｒａｓ核，得出正调和函数和（抛物）热函数的某些分形性质     

Some properties of elements of the prime field

We obtain some properties of primitive roots in the groups of residue class modulo prime number, in particular, Fermat primes and Sophie Germain primes. We also obtain some formulas for computation of products of elements in some subsets of the prime field of positive characteristic.     

Some properties of graphs of closed operators

In this paper we study some properties of graphs of closed operators in Hilbert spaces. We construct representations of von Neumann algebras induced by graphs of closed operators. We describe some classes of closed operators in terms of their characteristic matrices and study some properties of operations on graphs of closed operators.     

Estimation of cusp location of stochastic processes: a survey

We present a review of some recent results on estimation of location parameter for several models of observations with cusp-type singularity at the change point. We suppose that the cusp-type models fit better to the real phenomena described usually by change point models. The list of models includes Gaussian, inhomogeneous Poisson, ergodic diffusion processes, time series and the classical case of i.i.d. observations. We describe the properties of the maximum likelihood and Bayes estimators under some asymptotic assumptions. The asymptotic efficiency of estimators are discussed as well and the results of some numerical simulations are presented. We provide some heuristic arguments which demonstrate the convergence of log-likelihood ratios in the models under consideration to the fractional Brownian motion.     

Existence and structure results on almost periodic solutions of difference equations

We study the almost periodic solutions of Euler equations and of some more general Difference Equations. We consider two different notions of almost periodic sequences, and we establish some relations between them. We build suitable sequences spaces and we prove some properties of these spaces. We also prove properties of Nemytskii operators on these spaces. We build a variational approach to establish existence of almost periodic solutions as critical points, We obtain existence theorems fornonautonomous linear equations and for an Euler equation with a concave and coercive Lagrangian. We also use a Fixed Point approach to obtain existence results for quasi-linear Difference Equations.     

A survey of information-based complexity

We survey some recent results in information-based complexity. We focus on the worst case setting and also indicate some average case results.     

The structure of sets with few sums along a graph

We present common generalizations of some structure results of Freiman, Ruzsa, Balog-Szemerédi and Laczkovich-Ruzsa. We also give some applications to Combinatorial Geometry and Algebra, some of which generalize the aforementioned structure results even further.     

关于Gpp环和Gp-内射模的若干讨论

讨论了Gpp环和Gp-内射模的一些性质;讨论了Gp-内射模和R-内射模的关系及Gp-内射模和Gpp环的若干联系.最后讨论了和Gpp环有关的有限生成模的投射盖问题.     

关于局部随机吸引子若干性质的注记(英文)

In this note, we study some properties of local random pull-back attractors on compact metric spaces. We obtain some relations between attractors and their fundamental neighborhoods and basins of attraction. We also obtain some properties of omega-limit sets, as well as connectedness of random attractors. A simple deterministic example is given to illustrate some confusing problems.     

On the distributions of boundary values of Cauchy integrals

We use new methods to give short proofs to some known results on the distributions of boundary values of Cauchy integrals. We also indicate some further generalizations.

     

Continuous selections of multifunctions with weakly convex values

We obtain some selection theorems for multifunctions with weakly convex values. For this purpose, some new properties of weakly convex sets in a Hilbert space are investigated. We also present some examples showing the importance of various assumptions in these selection theorems.     

On the growth of meromorphic solutions of the Schwarzian differential equations

We study the properties of meromorphic solutions of the Schwarzian differential equations in the complex plane by using some techniques from the study of the class Wp. We find some upper bounds of the order of meromorphic solutions for some types of the Schwarzian differential equations. We also show that there are no wandering domains nor Baker domains for meromorphic solutions of certain Schwarzian differential equations.     

常用离散型随机变量的高阶原点矩

对离散型随机变量的高阶矩进行了研究,给出了几类离散型随机变量的高阶原点矩的统一递推公式,得到了离散型随机变量的高阶原点矩的形式特征.     

On maximal chains of systems of word equations

We consider systems of word equations and their solution sets. We discuss some fascinating properties of those, namely the size of a maximal independent set of word equations, and proper chains of solution sets of those. We recall the basic results, extend some known results and formulate several fundamental problems of the topic.     

Sets convex in a cone of directions

We consider sets which are convex in directions from some cone K. We generalize some well-known properties of ordinary convex sets for the case of K-convex sets and give some applications in optimization theory.     

Global Optimal Solutions of Noncyclic Mappings in Metric Spaces

We study some minimization problems for noncyclic mappings in metric spaces. We then apply the solution to obtain some results in the theory of analytic functions.     

Conditions for swappability of records in a microdata set when some marginals are fixed

We consider swapping of two records in a microdata set for the purpose of disclosure control. We give some necessary and sufficient conditions that some observations can be swapped between two records under the restriction that a given set of marginals are fixed. We also give an algorithm to find another record for swapping if one wants to swap out some observations from a particular record.     

The analysis of the stability of some integer programming algorithms with respect to the objective function

In this paper we define the notion of the stability with respect to the objective function for a wide class of integer linear programming algorithms. We study the stability of some of them under small variations of coefficients in the objective function. We prove the existence of both stable and unstable versions of the L-class enumeration algorithms. We show that some branch and bound algorithms, as well as some decomposition algorithms with Benders cuts, are unstable. We propose a modification of the considered decomposition algorithms that makes the latter stable with respect to the objective function.