Fixed points and selections of multifunctions on spaces with convexity

Relations among Gauge and Pettis integrals for $cwk(X)$-valued multifunctions

The aim of this paper is to study relationships among "gauge integrals" (Henstock, Mc Shane, Birkhoff) and Pettis integral of multifunctions whose values are weakly compact and convex subsets of a general Banach space, not necessarily separable. For this purpose we prove the existence of variationally Henstock integrable selections for variationally Henstock integrable multifunctions. Using this and other known results concerning the existence of selections integrable in the same sense as the corresponding multifunctions, we obtain three decomposition theorems. As applications of such decompos…

Uniform convexity and the splitting problem for selections

We continue to investigate cases when the Repovš-Semenov splitting problem for selections has an affirmative solution for continuous set-valued mappings. We consider the situation in infinite-dimensional uniformly convex Banach spaces. We use the notion of Polyak of uniform convexity and modulus of uniform convexity for arbitrary convex sets (not necessary balls). We study general geometric properties of uniformly convex sets. We also obtain an affirmative solution of the splitting problem for selections of certain set-valued mappings with uniformly convex images.

具有 RNP 的 Banach 空间中的条件期望

Conditional Expectations in Banach spaces with RNP

本文研究具有 RNP 的 Banach 空间中多值函数的条件期望，利用提升证明其 Effros 可测条件期望存在并给出拟选择表示，且应用于 Pettis 可积多值函数鞅。

Max-plus convexity in Riesz spaces

We study max-plus convexity in an Archimedean Riesz space $E$ with an order unit $\un$; the definition of max-plus convex sets is algebraic and we do not assume that $E$ has an {\it a priori} given topological structure. To the given unit $\un$ one can associate two equivalent norms $\norm\cdot\norm_{\un}$ and $\norm\cdot\norm_{\hun}$ on $E$; the distance ${\sf D}_{\hun}$ on $E$ associated to $\norm\cdot\norm_{\hun}$ is a geodesic distance for which max-plus convex sets in $E$ are geodesically closed sets. Under suitable assumptions, we establish max-plus versions of some fixed points and cont…

On affine selections of set-valued functions

The main result states that every convex set-valued function defined on a real interval with compact values in a locally convex space, admits an affine selection. In the case if the target space is a real line and the values are closed real intervals, we can replace the convexity assumption by the more general condition.