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In this paper, we study the existence of fixed points for mappings defined on complete, (sequentially compact) cone metric spaces, satisfying a general contractive inequality depending of two additional mappings.

Functional Analysis · Mathematics 2015-02-17 José R. Morales , Edixon Rojas

We define E-theory for separable C*-algebras over second countable topological spaces and establish its basic properties. This includes an approximation theorem that relates the E-theory over a general space to the E-theories over finite…

K-Theory and Homology · Mathematics 2015-10-23 Marius Dadarlat , Ralf Meyer

We discuss some results concerning fixed point equations in the setting of topological *-algebras of unbounded operators. In particular, an existence result is obtained for what we have called {\em weak $\tau$ strict contractions}, and some…

Mathematical Physics · Physics 2007-05-23 F. Bagarello

We give some new characterizations of unitaries, isometries, unital operator spaces, unital function spaces, operator systems, C*-algebras, and related objects. These characterizations only employ the vector space and operator space…

Operator Algebras · Mathematics 2008-05-23 David P. Blecher , Matthew Neal

The paper introduces the class of O-metric spaces, a novel generalization of metric-type spaces, classifying almost all possible metric types into upward and downward O-metrics. We list some topologies arising from O-metrics and discuss…

General Mathematics · Mathematics 2025-04-29 Hallowed O. Olaoluwa , Aminat O. Ige , Johnson O. Olaleru

In this paper we study the notion of Gerghaty type contractive mapping via simulation function along with $\mathcal{C}$-class functions and prove the existence of several fixed point results in ordinary and partially ordered metric spaces.…

Functional Analysis · Mathematics 2018-10-26 Azhar Hussain , Muhammad Ishfaq , Tanzeela Kanwal , Stojan Radenović

We study bounded bilinear maps on a C$^*$-algebra $A$ having product property at $c\in A$. This leads us to the question of when a C$^*$-algebra is determined by products at $c.$ In the first part of our paper, we investigate this question…

Operator Algebras · Mathematics 2023-12-04 Jorge J. Garcés , Mykola Khrypchenko

In this paper we introduce a notion of Morita equivalence for Hilbert C*-modules in terms of the Morita equivalence of the algebras of compact operators on Hilbert C*-modules. We investigate some properties of the new version of Morita…

Operator Algebras · Mathematics 2012-04-24 Maria Joita , Mohammad Sal Moslehian

The class of O-metric spaces generalize several existing metric-types in literature including metric spaces, b-metric spaces, and ultra metric spaces. In this paper, we discuss the properties of the topology induced by an O-metric and…

General Mathematics · Mathematics 2025-04-29 Hallowed O. Olaoluwa , Aminat O. Ige , Johnson O. Olaleru

In this paper, our aim is to obtain new fixed-disc results on metric spaces. To do this, we present a new approach using the set of simulation functions and some known fixed-point techniques. We do not need to have some strong conditions…

Metric Geometry · Mathematics 2025-06-03 Nihal Yilmaz Özgür

The classical Gelfand--Naimark theorems provide important insight into the structure of general and of commutative C*-algebras. It is shown that these can be generalized to certain ordered *-algebras. More precisely, for $\sigma$-bounded…

Operator Algebras · Mathematics 2022-03-24 Matthias Schötz

In this paper, we investigate *-homomorphisms between C*-algebras associated to \'etale groupoids. First, we prove that such a *-homomorphism can be described by closed invariant subsets, groupoid homomorphisms and cocycles under some…

Operator Algebras · Mathematics 2023-08-24 Fuyuta Komura

The aim of the present paper is to describe self-duality and C*- reflexivity of Hilbert {\bf A}-modules $\cal M$ over monotone complete C*-algebras {\bf A} by the completeness of the unit ball of $\cal M$ with respect to two types of…

funct-an · Mathematics 2025-04-29 Michael Frank

This article presents a deep investigation of fixed points for multivalued weak contractions in cone metric spaces. We extend Berinde weak contraction principles to the multivalued setting in cone metric spaces, developing existence,…

Functional Analysis · Mathematics 2025-08-13 Elvin Rada

In this paper, we investigate certain submodules in C*-algebras associated to effective \'etale groupoids. First, we show that a submodule generated by normalizers is a closure of the set of compactly supported continuous functions on some…

Operator Algebras · Mathematics 2024-04-12 Fuyuta Komura

This paper establishes new common fixed point theorems for weakly compatible mappings in metric spaces, relaxing traditional requirements such as continuity, compatibility, and reciprocal continuity. We present a unified framework for three…

General Mathematics · Mathematics 2025-07-02 Alemayehu Negash , Meaza Bogale

The main purpose of this work is to extend the properties of multivalued transformations to the integral type transformations and to obtain the existence of fixed points under F-contraction. In addition, the results of this study were…

General Mathematics · Mathematics 2020-02-04 Derya Sekman , Vatan Karakaya

We show that if $X$ is a complete metric space with uniform relative normal structure and $G$ is a subgroup of the isometry group of $X$ with bounded orbits, then there is a point in $X$ fixed by every isometry in $G$. As a corollary, we…

Functional Analysis · Mathematics 2023-06-08 Andrzej Wiśnicki

We shall introduce the notions of the strong Morita equivalence for unital inclusions of unital $C^*$-algebras and conditional expectations from an equivalence bimodule onto its closed subspace with respect to conditional expectations from…

Operator Algebras · Mathematics 2016-09-28 Kazunori Kodaka , Tamotsu Teruya

Recently many papers on cone metric spaces have been appeared, and main topological properties of such spaces have been obtained. A cone metric space is Hausdorff, and first countable, so the topology of it coincides with a topology induced…

General Topology · Mathematics 2012-07-25 AyŞE SÖnmez