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This paper presents new approaches to the fixed point property for nonexpansive mappings in L^1 spaces. While it is well-known that L^1 fails the fixed point property in general, we provide a complete and self-contained proof that…

泛函分析 · 数学 2025-09-15 Faruk Alpay , Hamdi Alakkad

We show that the typical nonexpansive mapping on a small enough subset of a CAT($\kappa$)-space is a contraction in the sense of Rakotch. By typical we mean that the set of nonexpansive mapppings without this property is a $\sigma$-porous…

泛函分析 · 数学 2021-08-06 Christian Bargetz , Michael Dymond , Emir Medjic , Simeon Reich

Hurewicz' characterized the dimension of separable metrizable spaces by means of finite-to-one maps. We investigate whether this characterization also holds in the class of compact F-spaces of weight c. Our main result is that, assuming the…

一般拓扑 · 数学 2014-01-15 Klaas Pieter Hart , Jan van Mill

In this paper we present some bounds of Hausdorff measures of objects definable in o-minimal structures: sets, fibers of maps, inverse images of curves of maps, etc. Moreover, we also give some explicit bounds for semi-algebraic or…

微分几何 · 数学 2012-04-27 Ta Le Loi , Phan Phien

Let Y be a locally convex Hausdorff space, K \subset E a cone and \leq_K the partial order defined by K. Let (X, p) be a TV S- cone metric space, {\phi} : K \rightarrow K a vectorial comparison function and f : X \rightarrow X such that…

泛函分析 · 数学 2011-11-15 Ion Olaru

This study focuses on defining normal and strictly convex structures within Menger cone PM-space. It also presents a shared fixed point theorem for the existence of two self-mappings constructed on a strictly convex probabilistic cone…

泛函分析 · 数学 2024-09-25 M. H. M. Rashid

In recent work, the authors developed a simple method of constructing topological spaces from certain well-behaved partially ordered sets -- those coming from sequences of relations between finite sets. This method associates a given poset…

一般拓扑 · 数学 2025-09-11 Adam Bartoš , Tristan Bice , Alessandro Vignati

We review the motivation and fundamental properties of the Hausdorff dimension of metric spaces and illustrate this with a number of examples, some of which are expected and well-known. We also give examples where the Hausdorff dimension…

动力系统 · 数学 2007-08-21 Dierk Schleicher

Completely positive trace-preserving maps $S$, also known as quantum channels, arise in quantum physics as a description of how the density operator $\rho$ of a system changes in a given time interval, allowing not only for unitary…

数学物理 · 物理学 2024-11-25 Roderich Tumulka , Jonte Weixler

The major motives of this paper are to study different types of contractive mappings and also to answer an open question of Garai et al. [The contractive principle for mappings in $b_v(s)$-metric spaces, arXiv:1802.03136]. We first set up…

度量几何 · 数学 2020-05-12 Pratikshan Mondal , Hiranmoy Garai , Lakshmi Kanta Dey

We construct a one dimensional, second countable, simply connected manifold that exhibits a single non Hausdorff fiber, sufficient to destroy the fundamental properties of classical covering space theory. The space, called the line with k…

一般拓扑 · 数学 2025-07-01 Abhiram Sripat

We study orbit spaces of generalized gradient vector fields for Morse functions. Typically, these orbit spaces are non-Hausdorff. Nevertheless, they are quite structured topologically and are amenable to study. We show that these orbit…

动力系统 · 数学 2014-08-06 Jack S. Calcut , Robert E. Gompf

The aim of this paper is to provide characterizations of a Meir-Keeler type mapping and a fixed point theorem for the mapping in a metric space endowed with a transitive relation.

泛函分析 · 数学 2025-09-17 Koji Aoyama , Masashi Toyoda

We consider the topological behaviors of continuous maps with one topological attractor on compact metric space $X$. This kind of map is a generalization of maps such as topologically expansive Lorenz map, unimodal map without homtervals…

动力系统 · 数学 2024-05-21 Yiming Ding , Yun Sun

We give a definition of mass for conformally compactifiable initial data sets. The asymptotic conditions are compatible with existence of gravitational radiation, and the compactifications are allowed to be polyhomogeneous. We show that the…

广义相对论与量子宇宙学 · 物理学 2007-05-23 P. T. Chrusciel , J. Jezierski , S. Leski

In this paper, we present the Brouwer-Schauder-Tychonoff fixed point theorem on locally convex spaces as the following extension and improvement: Suppose that S is a compact star-shaped subset with respect to p in S with its convexity index…

泛函分析 · 数学 2026-02-11 Lixin Cheng , Chulei Liu , Wen Zhang

In 1914, F. Hausdorff defined a metric on the set of closed subsets of a metric space $X$. This metric induces a topology on the set $H$ of compact subsets of $X$, called the Hausdorff topology. We show that the topological space $H$…

代数几何 · 数学 2016-01-12 W. D. Gillam , A. Karan

We show that (for the weak operator topology) the set of unitary operators on a separable infinite-dimensional Hilbert space is residual in the set of all contractions. The analogous result holds for isometries and the strong operator…

泛函分析 · 数学 2014-12-02 Tanja Eisner

We study the non-wandering set of contracting Lorenz maps. We show that if such a map $f$ doesn't have any attracting periodic orbit, then there is a unique topological attractor. Precisely, there is a compact set $\Lambda$ such that…

动力系统 · 数学 2016-12-02 Paulo Brandão

A general fixed point theorem for isometries in terms of metric functionals is proved under the assumption of the existence of a conical bicombing. It is new even for isometries of Banach spaces as well as for non-locally compact…

泛函分析 · 数学 2023-01-19 Anders Karlsson