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Given a Tychonoff space $X$, let $\varrho(X)$ be the set of remote points of $X$. We view $\varrho(X)$ as a topological space. In this paper we assume that $X$ is metrizable and ask for conditions on $Y$ so that $\varrho(X)$ is homeomorphic…

General Topology · Mathematics 2018-09-19 Rodrigo Hernández-Gutiérrez , Michael Hrušák , Angel Tamariz-Mascarúa

In a previous article by the author and P. Wesolek, it was shown that a compactly generated locally compact group $G$ admits a finite normal series $(G_i)$ in which the factors are compact, discrete or irreducible in the sense that no…

Group Theory · Mathematics 2021-06-30 Colin D. Reid

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

It is well-known that every non-isolated point in a compact Hausdorff space is the accumulation point of a discrete subset. Answering a question raised by Z. Szentmiklossy and the first author, we show that this statement fails for…

General Topology · Mathematics 2013-07-09 Istvan Juhasz , Saharon Shelah

A space is nearly pseudocompact if and only if $\upsilon X\backslash X$ is dense in $\beta X\backslash X$. If we denote $K=cl_{\beta X}(\upsilon X\backslash X)$, then $\delta X=X\cup(\beta X\backslash K)$ is referred by Henriksen and…

General Topology · Mathematics 2022-03-28 Biswajit Mitra , Sanjib Das

We study when a piecewise full group (a.k.a. topological full group) of homeomorphisms of the Cantor space $X$ can be given a non-discrete totally disconnected locally compact (t.d.l.c.) topology and give a criterion for the alternating…

Group Theory · Mathematics 2025-01-03 Alejandra Garrido , Colin D. Reid

In a recent paper \cite{T} the fact that a class of locally compact metric spaces $X$, among which are Euclidean spaces, are not homemorphic to their punctured version $X\men\{p\}$, was given an interesting new proof which does not use…

General Topology · Mathematics 2023-08-08 Giuseppe De Marco

We show that if $X$ is a separable locally compact Hausdorff connected space with fewer than $\mathfrak c$ non-cut points, then $X$ embeds into a dendrite $D\subseteq \mathbb R ^2$, and the set of non-cut points of $X$ is a nowhere dense…

General Topology · Mathematics 2019-09-25 David S. Lipham

A compact space $X$ is said to be minimal if there exists a map $f:X\to X$ such that the forward orbit of any point is dense in $X$. We consider rigid minimal spaces, motivated by recent results of Downarowicz, Snoha, and Tywoniuk [J. Dyn.…

Dynamical Systems · Mathematics 2020-02-13 J. P. Boroński , Jernej Činč , Magdalena Foryś-Krawiec

We present a reachability based approach to establish unique ergodicity of non-linear filter processes where state space of a hidden Markov model is a compact Polish metric space and the observation space is a Polish metric space. We also…

Probability · Mathematics 2025-09-16 Yunus Emre Demirci , Serdar Yüksel

[Abridged] Over the years, several compact group catalogues have been built using different methods, but most of them are not deep enough to go beyond the very local universe with a high level of redshift completeness. We build…

Astrophysics of Galaxies · Physics 2024-10-30 A. Zandivarez , E. Diaz-Gimenez , A. Taverna , F. Rodriguez , M. Merchan

We show that in the $\mathbb{P}_{\max}$ extension of a certain Chang-type model of determinacy, if $\kappa\in\{\omega_1, \omega_2, \omega_3\}$, then the restriction of the club filter on $\kappa\cap\mathrm{Cof}(\omega)$ to HOD is an…

Logic · Mathematics 2025-07-01 Navin Aksornthong , Takehiko Gappo , James Holland , Grigor Sargsyan

We study partition properties for uncountable regular cardinals that arise by restricting partition properties defining large cardinal notions to classes of simply definable colourings. We show that both large cardinal assumptions and…

Logic · Mathematics 2018-07-03 Philipp Lücke

We introduce a general method of constructing locally compact scattered spaces from certain families of sets and then, with the help of this method, we prove that if kappa^{<kappa}=kappa then there is such a space of height kappa^+ with…

Logic · Mathematics 2007-05-23 Istvan Juhász , Saharon Shelah , Lajos Soukup , Zoltan Szentmiklóssy

We present a simplified treatment of stability of filtrations on finite spaces. Interestingly, we can lift the stability result for combinatorial filtrations from [CSEM06] to the case when two filtrations live on different spaces without…

Algebraic Topology · Mathematics 2017-12-14 Facundo Memoli

We use a natural forcing to construct a left-separated topology on an arbitrary cardinal kappa. The resulting left-separated space X_kappa is also 0-dimensional T_2, hereditarily Lindelof, and countably tight. Moreover if kappa is regular…

Logic · Mathematics 2007-05-23 Istvan Juhász , Saharon Shelah

The category of monotone determined spaces is an extended topological framework for dcpos in domain theory. We first show that monotone determined spaces are exactly the spaces generated by one-point convergence spaces, and then naturally…

General Topology · Mathematics 2026-05-26 Yuxu Chen , Hui Kou , Zhenchao Lyu

In this paper we analyze the connection between some properties of partially strongly compact cardinals: the completion of filters of certain size and instances of the compactness of $\mathcal{L}_{\kappa,\kappa}$. Using this equivalence we…

Logic · Mathematics 2018-09-18 Yair Hayut

Assuming the existence of certain large cardinal numbers, we prove that for every projective filter $\mathscr F$ over the set of natural numbers, $\mathscr{F}$-bases in Banach spaces have continuous coordinate functionals. In particular,…

Functional Analysis · Mathematics 2020-10-21 Tomasz Kania , Jarosław Swaczyna

We construct a consistent example of a topological space $Y=X \cup \{\infty\}$ such that: 1) $Y$ is regular. 2) Every $G_\delta$ subset of $Y$ is open. 3) The point $\infty$ is not isolated, but it is not in the closure of any discrete…

General Topology · Mathematics 2024-03-05 Santi Spadaro , Paul Szeptycki