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Intermediate rings of real valued continuous functions with countable range on a Hausdorff zero-dimensional space $X$ are introduced in this article. Let $\Sigma_c(X)$ be the family of all such intermediate rings $A_c(X)$'s which lie…

General Topology · Mathematics 2019-12-05 Sudip Kumar Acharyya , Rakesh Bharati , A. Deb Ray

Let $X$ be a zero-dimensional space and $C_c(X)$ be the set of all continuous real valued functions on $X$ with countable image. In this article we denote by $C_c^K(X)$ (resp., $C_{c}^{\psi}(X)$) the set of all functions in $C_c(X)$ with…

General Topology · Mathematics 2015-07-01 Alireza Olfati

Consider the ring $C_c(X)_F$ of real valued functions which are discontinuous on a finite set with countable range. We discuss $(\mathcal{Z}_c)_F$-filters on $X$ and $(\mathcal{Z}_c)_F$-ideals of $C_c(X)_F$. We establish an analogous…

General Topology · Mathematics 2023-10-04 Achintya Singha , D. Mandal , Samir Ch Manda , Sagarmoy Bag

A proper ideal $I$ in a commutative ring with unity is called a $z^\circ$-ideal if for each $a$ in $I$, the intersection of all minimal prime ideals in $R$ which contain $a$ is contained in $I$. For any totally ordered field $F$ and a…

General Topology · Mathematics 2017-12-25 Sagarmoy Bag , Sudip Kumar Acharyya , Dhananjoy Mandal

Let K be an expansion of either an ordered field or a valued field. Given a definable set X $\subseteq$ K<sup>m</sup> let C(X) be the ring of continuous definable functions from X to K. Under very mild assumptions on the geometry of X and…

Logic · Mathematics 2018-10-31 Luck Darnière , Marcus Tressl

Let $\mathcal{P}$ be an ideal of closed subsets of a topological space $X$. Consider the ring, $C(X)_\mathcal{P}$ of real valued functions on $X$ whose closure of discontinuity set is a member of $\mathcal{P}$. We investigate the ring…

General Topology · Mathematics 2023-04-18 Amrita Dey , Sudip Kumar Acharyya , Sagarmoy Bag , Dhananjoy Mandal

For a nonempty topological space X, the ring of all real-valued functions on $X$ with pointwise addition and multiplication is denoted by $F(X)$ and continuous members of $F(X)$ is denoted by $C(X)$. Let $A(X)$ be a subring of $F(X)$ and…

General Topology · Mathematics 2021-07-06 Mohammad Reza Ahmadi Zand

For a compactification $\alpha X$ of a Tychonoff space $X$, the algebra of all functions $f\in C(X)$ that are continuously extendable over $% \alpha X$ is denoted by $C_{\alpha}(X)$. It is shown that, in a model of $\textbf{ZF}$, it may…

General Topology · Mathematics 2018-05-25 Kyriakos Keremedis , Eliza Wajch

Consider the subring $\mathcal{R}_cL$ of continuous real-valued functions defined on a frame $L$, comprising functions with a countable pointfree image. We present some useful properties of $\mathcal{R}_cL$. We establish that both…

Functional Analysis · Mathematics 2024-08-13 Mostafa Abedi

If $I$ is an ideal in the ring $C(X)$ of all real valued continuous functions defined over a Tychonoff space $X$, then $X$ is called $I$-$pseudocompact$ if the set $X\setminus \bigcap Z[I]$ is a bounded subset of $X$. Corresponding to $I$,…

General Topology · Mathematics 2026-01-29 Soumajit Dey , Sudip Kumar Acharyya , Dhananjoy Mandal

The concept of Hausdorff continuous interval valued functions, developed within the theory of Hausdorff approximations and originaly defined for interval valued functions of one real variable is extended to interval valued functions defined…

Analysis of PDEs · Mathematics 2007-05-23 Roumen Anguelov

A completely regular Hausdorff space $X$ is called a $WCF$-space if every pair of disjoint cozero-sets in $X$ can be separated by two disjoint $Z^{\circ}$-sets. The class of $WCF$-spaces properly contains both the class of $F$-spaces and…

General Topology · Mathematics 2026-02-12 A. R. Aliabad , A. Taherifar

A topological space $X$ is said to be an Ascoli space if any compact subset $K$ of $C_k(X)$ is evenly continuous. This definition is motivated by the classical Ascoli theorem. We study the $k_R$-property and the Ascoli property of…

General Topology · Mathematics 2016-11-18 Saak Gabriyelyan , Jan Grebik , Jerzy Kakol , Lyubomyr Zdomskyy

we prove that if $X$ is a locally compact $\sigma$-compact space then on its quotient, $\gamma(X)$ say, determined by the algebra of all real valued bounded continuous functions on $X$, the quotient topology and the completely regular…

General Topology · Mathematics 2008-11-21 Aldo J. Lazar

Let $Y$ be a metrizable space containing at least two points, and let $X$ be a $Y_{\mathcal{I}}$-Tychonoff space for some ideal $\mathcal{I}$ of compact sets of $X$. Denote by $C_{\mathcal{I}}(X,Y)$ the space of continuous functions from…

General Topology · Mathematics 2020-04-14 Saak Gabriyelyan , Alexander V. Osipov

The set of all maximal ideals of the ring $\mathcal{M}(X,\mathcal{A})$ of real valued measurable functions on a measurable space $(X,\mathcal{A})$ equipped with the hull-kernel topology is shown to be homeomorphic to the set $\hat{X}$ of…

Functional Analysis · Mathematics 2018-06-11 Sudip Kumar Acharyya , Sagarmoy Bag , Joshua Sack

We prove that the locally convex space $C_{p}(X)$ of continuous real-valued functions on a Tychonoff space $X$ equipped with the topology of pointwise convergence is distinguished if and only if $X$ is a $\Delta$-space in the sense of \cite…

General Topology · Mathematics 2020-12-01 Jerzy Kakol , Arkady Leiderman

We prove that for any topological space $X$ of countable tightness, each \sigma-convex subspace $\F$ of the space $SC_p(X)$ of scatteredly continuous real-valued functions on $X$ has network weight $nw(\F)\le nw(X)$. This implies that for a…

General Topology · Mathematics 2013-06-04 Taras Banakh , Bogdan Bokalo , Nadiya Kolos

The aim of this paper is to give a characterization of path connected topological fields, inspired by the classical Gelfand correspondence between a compact Hausdorff topological space $X$ and the space of maximal ideals of the ring of real…

General Topology · Mathematics 2019-03-20 Xavier Caicedo , Guillermo Mantilla-Soler

In this paper we consider the relationship between order and topology in the vector lattice $C_b(X)$ of all bounded continuous functions on a Hausdorff space $X$. We prove that the restriction of $f\in C_b(X)$ to a closed set $A$ induces an…

Functional Analysis · Mathematics 2019-11-18 Marko Kandić , Aleš Vavpetič
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