集值 Pramart 的鞅分解

研究了集值Pramart的若干性质,利用支撑函数得到了集值Pramart的收敛定理,同时,证明了实值Pramart的鞅分解定理.以此为基础,给出了集值Pramart在Kuratowski-Mosco意义下的鞅分解定理.     

关于集值Pramart的某些结果

本文引进了Boohner可积函数空间L~1[Ω;X]中子集的可分解包的概念,给出了集值随机变量族本性上确界的定义及基本性质。以此为基础,研究了集值Pramart的性质;用类似于实值Snell包的方法给出了集值superpramart的上鞅逼近,证明了集值superpramart在Kuratowski-Mosco意义下的收敛定理。     

集值Superpramart的上鞅逼近

文中讨论了可积随机集条件期望的若干性质,在此基础上给出了集值Ｓｕｐｅｒｐｒａｍａｒｔ的上鞅逼近,同时,证明了集值Ｓｕｐｅｒｐｒａｍａｒｔ 在Ｋｕｒａｔｏｗｓｋｉ－Ｍｏｓｃｏ意义下的收敛定理。     

集值L^1—极限鞅的集值鞅逼近及其收敛性

本文证明了集值Ｌ~１－极限鞅的集值鞅逼近定理,并利用此结果以及集值鞅的收敛性结果讨论了集值Ｌ~１－极限鞅的收敛性．     

集值拟鞅和集值一致渐近鞅

本文讨论了集值拟鞅和集值一致渐近鞅,证明了集值拟鞅与集值一致渐近鞅的选样定理,对于集值一致渐近鞅得到了一些收敛性结果,并由此刻化了空间的 Radon-Nikodym性质.     

集值下(上)鞅的 Doob 分解

本文研究集值下(上)鞅的 Doob 分解.我们得到一些确保 Doob 分解存在的充要条件,并给出例子说明并非所有集值下(上)鞅都有 Doob 分解.     

集值L1极限鞅导出的集值测度

讨论集值L1极限鞅的一些性质,在此基础上,研究集值L1极限鞅导出的集值测度及其性质.     

集值局部平方可积鞅

介绍集值类（D）过程和集值局部鞅的概念和有关性质，进而讨论了集值局部平方可积鞅的概念和性质。     

集值上鞅的收敛定理及 Riesz 分解

本文给出了集值鞅的进一步性质;建立了集值上鞅外穿不等式;证明了一个集值上鞅收敛定理;研究了集值上鞅的 Riesz 分解.     

集值序上鞅

本文研究了连续时间的集值序上鞅．在一定的条件下首先证明了集值序上鞅有（Ｋ－Ｍ）Ｒｉｅｓｚ分解;然后证明了集值序上鞅的Ｄｏｏｂ－停时定理．     

Korovkin-type approximation in spaces of vector-valued and set-valued functions

We consider some Korovkin-type approximation results for sequences of linear continuous operators in spaces of vector-valued and set-valued continuous functions without assuming the existence of the limit operator. Even in spaces of real continuous functions, where similar results have already been established, we replace the positivity assumption with a weaker condition. We also give some quantitative estimate of the convergence and some applications where previous results cannot be applied.     

Nonlinear Chebyshev approximation to set-valued functions

In this paper, we give a characterization of best Chebyshev approximation to set-valued functions from a family of continuous functions with the weak betweeness property. As a consequence, we obtain a characterization of Kolmogorov type for best simultaneous approximation to an infinity set of functions. We introduce the concept of a set-sun and give a characterization of it. In addition, we prove a property of Amir–Ziegler type for a family of real functions and we get a characterization of best simultaneous approximation to two functions     

A theorem on martingale selection for relatively open convex set-valued random sequences

For set-valued random sequences (G _n) _n=0 ^N with relatively open convex values G _n(ω), we prove a new test for the existence of a sequence (x _n) _n=0 ^N of selectors adapted to the filtration and admitting an equivalent martingale measure. The statement is formulated in terms of the supports of regular upper conditional distributions of G _n. This is a strengthening of the main result proved in our previous paper [1], where the openness of the set G _n(ω) was assumed and a possible weakening of this condition was discussed.     

Approximation theorems for set-valued stochastic integrals

The article is devoted to new properties of Aumann, Lebesgue, and Itô set-valued stochastic integrals considered in papers [1 Kisielewicz, M. (2014). Properties of generalized set-valued stochastic integrals. Discuss. Math. (DICO) 34:131–147. [Google Scholar],2 Kisielewicz, M., Michta, M. (2017). Integrably bounded set-valued stochastic integrals. J. Math. Anal. Appl. 449:1893–1910.[Crossref], [Web of Science ®] , [Google Scholar]]. In particular, it contains some approximation theorems for Aumann and Itô set-valued stochastic integrals. Hence, in particular, it follows that Aumann and Lebesgue set-valued stochastic integrals cover a.s., both for measurable and IF-nonanticipative integrably bounded set-valued stochastic processes.     

Approximation of continuous set-valued maps by constant set-valued maps with image balls

It is shown that the problem of the best uniform approximation in the Hausdorff metric of a continuous set-valued map with finite-dimensional compact convex images by constant set-valued maps whose images are balls in some norm can be reduced to a visual geometric problem. The latter consists in constructing a spherical layer of minimal thickness which contains the complement of a compact convex set to a larger compact convex set.     

Interpolation on weak martingale Hardy space

By the weak atomic decompositions of weak martingale Hardy spaces, we investigate the interpolation spaces between weak martingale Hardy spaces and martingale Hardy spaces.     

鞅空间的原子分解与有限鞅的稠密性

引入了原子鞅与正则原子鞅概念、并研究了两类Banach空间值鞅Hardy空间的原子分解和有限鞅的稠密性,所得结论揭示了鞅Hardy空间正则原子鞅分解的存在性,有限鞅的稠密性和Banach空间的一致光滑性（或一致凸性）三者之间的内在联系．     

关于集值上鞅分解式的注记

讨论了集值上鞅与支撑函数的一些性质,利用支撑函数研究了一般Banach空间上集值上鞅的Riesz分解定理,推广和改进了以往的结果。     

Multi-segmental representations and approximation of set-valued functions with 1D images

In this work univariate set-valued functions (SVFs, multifunctions) with 1D compact sets as images are considered. For such a continuous SFV of bounded variation (CBV multifunction), we show that the boundaries of its graph are continuous, and inherit the continuity properties of the SVF. Based on these results we introduce a special class of representations of CBV multifunctions with a finite number of ‘holes’ in their graphs. Each such representation is a finite union of SVFs with compact convex images having boundaries with continuity properties as those of the represented SVF. With the help of these representations, positive linear operators are adapted to SVFs. For specific positive approximation operators error estimates are obtained in terms of the continuity properties of the approximated multifunction.