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Related papers: Normal Spaces via Urysohn's Lemma as a Lifting Pro…

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A strong generalized topological space is an ordered pair $\mathbf{X}=\langle X, \mathcal{T}\rangle$ such that $X$ is a set and $\mathcal{T}$ is a collection of subsets of $X$ such that $\emptyset, X\in \mathcal{T}$ and $\mathcal{T}$ is…

General Topology · Mathematics 2021-03-10 Jacek Hejduk , Eliza Wajch

Urysohn's Lemma is a crucial property of normal spaces that deals with separation of closed sets by continuous functions. It is also a fundamental ingredient in proving the Tietze Extension Theorem, another property of normal spaces that…

General Topology · Mathematics 2021-05-21 Florica C. Cîrstea

We introduce the notion of (hybrid) large scale normal space and prove coarse geometric analogues of Urysohn's Lemma and the Tietze Extension Theorem for these spaces, where continuous maps are replaced by (continuous and) slowly…

Metric Geometry · Mathematics 2018-10-23 Jerzy Dydak , Thomas Weighill

Hyperspaces form a powerful tool in some branches of mathematics: lots of fractal and other geometric objects can be viewed as fixed points of some functions in suitable hyperspaces - as well as interesting classes of formal languages in…

General Topology · Mathematics 2014-10-15 René Bartsch

We illustrate the generative power of the lifting property (orthogonality of morphisms in a category) as means of defining natural elementary mathematical concepts by giving a number of examples in various categories, in particular showing…

Category Theory · Mathematics 2017-07-21 Misha Gavrilovich

We observe that some natural mathematical definitions are lifting properties relative to simplest counterexamples, namely the definitions of surjectivity and injectivity of maps, as well as of being connected, separation axioms $T_0$ and…

History and Overview · Mathematics 2014-08-29 Misha Gavrilovich

In this paper we define a new space, $LH(X,Y)$, consisting of functions $f\in X \subset Y$ (with $X,Y$ normed spaces) such that $\| f \|_X \equiv \| f \|_Y$ (where $\| \cdot \|_X$ is any norm on $X$, in general not the norm induced by $\|…

Functional Analysis · Mathematics 2019-12-13 Manuel Norman

We observe that many of the separation axioms of topology (including $T_0-T_4$) can be expressed concisely and uniformly in terms of category theory as lifting properties (in the sense of Quillen model categories) with respect to (usually…

General Topology · Mathematics 2017-06-29 Misha Gavrilovich

The aim of this paper is to introduce a new class of softly normal called softly $\pi g\widehat{D}$ -normality by using $\pi g\widehat{D}$ -open sets and obtained several properties of such a space. We discuss many properties of this new…

General Topology · Mathematics 2025-06-12 Neeraj Kumar Tomar , Fahed Zulfeqarr , M. C. Sharma

In the article a technique of the usage of $f$-continuous functions (on mappings) and their families is developed. A proof of the Urysohn's Lemma for mappings is presented and a variant of the Brouwer-Tietze-Urysohn Extension Theorem for…

General Topology · Mathematics 2024-06-13 Mikhail Yourievich Liseev

Normality equations describe Newtonian dynamical systems admitting normal shift of hypersurfaces. They were first derived in Euclidean geometry, then in Riemannian geometry. Recently they were rederived in more general case, when geometry…

Differential Geometry · Mathematics 2007-05-23 Ruslan Sharipov

A classical result from topology called Uryshon's lemma asserts the existence of a continuous separator of two disjoint closed sets in a sufficiently regular topological space. In this work we make a search for this separator constructive…

Algebraic Geometry · Mathematics 2022-07-04 Milan Korda , Jean-Bernard Lasserre , Alexey Lazarev , Victor Magron , Simone Naldi

Two variations of classical Urysohn lemma for subsets of topological vector spaces are obtained in this article. The continuous functions constructed in these lemmas are of quasi-convex type.

Functional Analysis · Mathematics 2019-02-25 S. Ramkumar , C. Ganesa Moorthy

A space $X$ is called $Ps$-normal($Ps$-Tychonoff) space if there exists a normal(Tychonoff) space $Y$ and a bijection $f: X\mapsto Y$ such that $f\lvert_K:K\mapsto f(K)$ is homeomorphism for any pseudocompact subset $K$ of $X$. We establish…

General Topology · Mathematics 2019-07-23 Sagarmoy Bag , Ram Chandra Manna , Sourav Kanti Patra

We prove some extension theorems involving uniformly continuous maps of the universal Urysohn space. We also prove reconstruction theorems for certain groups of autohomeomorphisms of this space and of its open subsets.

Metric Geometry · Mathematics 2012-10-23 Wieslaw Kubiś , Matatyahu Rubin

This paper introduces and explores functions defined on \( H^* \)-normal spaces through the framework of \( H^* \)-open sets. We extend the concept of \( H^* \)-normality and investigate its connections with \( g \)-normal and classical…

General Topology · Mathematics 2025-07-10 Neeraj Kumar Tomar , M. C. Sharma , Amit Ujlayan

We are considering typed hierarchies of total, continuous functionals using complete, separable metric spaces at the base types. We pay special attention to the so called Urysohn space constructed by P. Urysohn. One of the properties of the…

Logic in Computer Science · Computer Science 2015-07-01 Dag Normann

A space $X$ is called $CCS$-normal space if there exist a normal space $Y$ and a bijection $f: X\mapsto Y$ such that $f\lvert_C:C\mapsto f(C)$ is homeomorphism for any cellular-compact subset $C$ of $X$. We discuss about the relations…

General Topology · Mathematics 2020-07-14 Sagarmoy Bag , Ram Chandra Manna , Asit Baran Raha

A fundamental problem in manifold learning is to approximate a functional relationship in a data chosen randomly from a probability distribution supported on a low dimensional sub-manifold of a high dimensional ambient Euclidean space. The…

Machine Learning · Computer Science 2023-07-11 H. N. Mhaskar , Ryan O'Dowd

Traditional neural embeddings represent concepts as points, excelling at similarity but struggling with higher-level reasoning and asymmetric relationships. We introduce a novel paradigm: embedding concepts as linear subspaces. This…

Machine Learning · Computer Science 2025-08-26 Gabriel Moreira , Zita Marinho , Manuel Marques , João Paulo Costeira , Chenyan Xiong
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