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Related papers: Nonstandard methods in large-scale topology

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We introduce a topology on the space of all isomorphism types represented in a given class of countable models, and use this topology as an aid in classifying the isomorphism types. This mixes ideas from effective descriptive set theory and…

Logic · Mathematics 2019-08-20 Russell Miller

John Roe \cite{Roe lectures} introduced coarse structures for arbitrary sets $X$ by considering subsets of $X\times X$. That definition, while natural for analysts, is a bit more difficult to digest for topologists and geometers. In this…

Metric Geometry · Mathematics 2007-05-23 J. Dydak , C. S. Hoffland

Generalized topological spaces in the sense of Cs\'{a}sz\'{a}r have two main features which distinguish them from typical topologies. First, these families of subsets are not closed under intersections. Second, we allow for the possibility…

Logic · Mathematics 2019-09-23 Tomasz Witczak

We apply methods of nonstandard mathematics in order to regard analytic geometry in a very different way. For example, complex spaces are seen to be the "standard part" of certain algebraic nonstandard schemes. We construct a category of…

Algebraic Geometry · Mathematics 2008-06-27 Adel Khalfallah , Siegmund Kosarew

We determine sufficient structure for an elementary topos to emulate E. Nelson's Internal Set Theory in its internal language, and show that any topos satisfying the internal axiom of choice occurs as a universe of standard objects and…

Category Theory · Mathematics 2023-09-07 José Siqueira

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

The bornological convergence structures that have been studied recently as generalizations of Attouch-Wets convergence define pretopologies on hyperspaces. In this paper we characterize the topological reflections of these pretopologies and…

General Topology · Mathematics 2013-04-10 Tom Vroegrijk

Coarse geometry is the study of large-scale properties of spaces. In this paper we study group coarse structures (i.e., coarse structures on groups that agree with the algebraic structures), by using group ideals. We introduce a large class…

General Topology · Mathematics 2019-05-15 Dikran Dikranjan , Nicolò Zava

A generalization of the triangle inequality is introduced by a mapping similar to a t-conorm mapping. This generalization leads us to a notion for which we use the $\star$-metric terminology. We are interested in the topological space…

General Topology · Mathematics 2020-09-03 Seyed Mohammad Amin Khatami , Madjid Mirzavaziri

Nonstandard graphs have been defined and examined in prior works. The present work does the same for nonstandard digraphs. Since digraphs have more structure than do graphs, the present discussion requires more complicated definitions and…

Combinatorics · Mathematics 2009-04-28 A. H. Zemanian

In this paper, we study some topological characteristics of the n-normed spaces. We observe convergence sequences, closed sets, and bounded sets in the n-normed spaces using norms of quotient spaces that will be constructed. These norms…

Functional Analysis · Mathematics 2018-10-19 Harmanus Batkunde , Hendra Gunawan

Non-Archimedean mathematics (in particular, nonstandard analysis) allows to construct some useful models to study certain phenomena arising in PDE's; for example, it allows to construct generalized solutions of differential equations and…

Logic · Mathematics 2015-12-18 Vieri Benci , Lorenzo Luperi Baglini

Coarse geometry, the branch of topology that studies the global properties of spaces, was originally developed for metric spaces and then Roe introduced coarse structures as a large-scale counterpart of uniformities. In the literature,…

General Topology · Mathematics 2018-05-29 Nicolò Zava

We define a class of spaces on which one may generalise the notion of compactness following motivating examples from higher-dimensional number theory. We establish analogues of several well-known topological results (such as Tychonoff's…

General Topology · Mathematics 2019-02-11 Raven Waller

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

In this paper, we consider certain topological properties along with certain types of mappings on these spaces defined by the notion of ideal convergence. In order to do that, we primarily follow in the footsteps of the earlier studies of…

General Topology · Mathematics 2023-01-03 Pratulananda Das , Upasana Samanta , Shou Lin

Let $X$ be a topological space. A subset of $C(X)$, the space of continuous real-valued functions on $X$, is a partially ordered set in the pointwise order. Suppose that $X$ and $Y$ are topological spaces, and $A(X)$ and $A(Y)$ are subsets…

Functional Analysis · Mathematics 2014-08-22 Denny H. Leung , Wee-Kee Tang

This commentary considers non-standard analysis and a recently introduced computational methodology based on the notion of \G1 (this symbol is called \emph{grossone}). The latter approach was developed with the intention to allow one to…

General Mathematics · Mathematics 2018-07-25 Yaroslav D. Sergeyev

In this paper we collect some open set-theoretic problems that appear in the large-scale topology (called also Asymptology). In particular we ask problems about critical cardinalities of some special (large, indiscrete, inseparated) coarse…

General Topology · Mathematics 2021-11-10 Taras Banakh , Igor Protasov

For real application and theoretical investigation of ordinary hypergraphs and non-ordinary hypergraphs, researchers need to establish standard rules and feasible operating methods. We propose a visualization tool for investigating…

History and Overview · Mathematics 2025-03-27 Fei Ma , Bing Yao