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Related papers: Condensations with extra properties

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We introduce a covering notion depending on two cardinals, which we call $\mathcal O $-$ [ \mu, \lambda ]$-compactness, and which encompasses both pseudocompactness and many other generalizations of pseudocompactness. For Tychonoff spaces,…

General Topology · Mathematics 2012-11-27 Paolo Lipparini

Generalizing classical descriptive set theory opens foundational questions about the Borel hierarchy. In this paper we systematically study those questions, working in the general framework of Polish-like spaces relative to an uncountable…

Logic · Mathematics 2025-11-20 Claudio Agostini , Nick Chapman , Luca Motto Ros , Beatrice Pitton

The structure of automorphism groups of $\kappa$-existentially closed groups are studied by Kaya-Kuzucuo\u{g}lu in 2022. It was proved that Aut(G) is the union of subgroups of level preserving automorphisms and $|Aut(G)|=2^\kappa$ whenever…

Logic · Mathematics 2024-09-04 Burak Kaya , Mahmut Kuzucuoğlu , Patrizia Longobardi , Mercede Maj

It is an interesting, maybe surprising, fact that different dense subspaces of even "nice" topological spaces can have different densities. So, our aim here is to investigate the set of densities of all dense subspaces of a topological…

General Topology · Mathematics 2021-09-23 Istvan Juhasz , Jan van Mill , Lajos Soukup , Zoltan Szentmiklossy

We discuss the existence of complete accumulation points of sequences in products of topological spaces. Then we collect and generalize many of the results proved in Parts I, II and IV. The present Part VI is complementary to Part V to the…

Logic · Mathematics 2009-04-22 Paolo Lipparini

By means of appropriate sparse bounds, we deduce compactness on weighted $L^p(w)$ spaces, $1<p<\infty$, for all Calder\'on-Zygmund operators having compact extensions on $L^2(\mathbb{R}^n)$. Similar methods lead to new results on…

Classical Analysis and ODEs · Mathematics 2024-07-23 Cody B. Stockdale , Paco Villarroya , Brett D. Wick

Some properties of skelatally generated spaces are established. In particular, it is shown that any compactum co-absolute to a $\kappa$-metrizable compactum is skeletally generated. We also prove that a compactum $X$ is skeletally generated…

General Topology · Mathematics 2014-04-15 V. Valov

We solve a long standing question due to Arhangel'skii by constructing a compact space which has a $G_\delta$ cover with no continuum-sized ($G_\delta$)-dense subcollection. We also prove that in a countably compact weakly Lindel\"of normal…

General Topology · Mathematics 2017-07-18 Santi Spadaro , Paul Szeptycki

In \cite{MbPe}, Mbombo and Pestov prove that the group of isometries of the generalized Urysohn space of density $\kappa$, for uncountable $\kappa$ such that $\kappa^{<\kappa}=\kappa$, is not a universal topological group of weight…

Logic · Mathematics 2018-02-09 Michal Doucha

We extend Deligne's original argument showing that locally coherent topoi have enough points, clarified using collage diagrams. We show that our refinement of Deligne's technique can be adapted to recover every existing result of this kind,…

Category Theory · Mathematics 2024-07-08 Ivan Di Liberti , Morgan Rogers

This paper generalizes sofic entropy theory, in both the topological and measure-theory settings, to actions of locally compact groups. We prove invariance under topological and measure conjugacy of these entropies and establish the…

Dynamical Systems · Mathematics 2023-11-07 Lewis Bowen

Modifying a construction of W. Marciszewski we prove (in ZFC) that there exists a subspace of the real line $\mathbb{R}$, such that the realcompact space $C_p(X)$ of continuous real-valued functions on $X$ with the pointwise convergence…

General Topology · Mathematics 2013-12-23 Mikołaj Krupski

A simplified construction is presented for Komj\'ath's result that for every uncountable cardinal $\kappa$, there are $2^\kappa$ graphs of size $\kappa$ none of them being a minor of another.

Combinatorics · Mathematics 2020-05-13 Max Pitz

Let $X$ be a locally compact topological space, $(Y,d)$ be a boundedly compact metric space and $LB(X,Y)$ be the space of all locally bounded functions from $X$ to $Y$. We characterize compact sets in $LB(X,Y)$ equipped with the topology of…

General Topology · Mathematics 2018-03-29 Ľubica Holá , Dušan Holý

We give different perspectives on the notion of shape for condensed anima. We prove that it recovers more classical notions of shape for topological spaces in the cases of all paracompact compactly generated spaces and all locally…

Algebraic Topology · Mathematics 2026-05-11 Catrin Mair

In this paper, we are interested in parallels to the classical notions of special subsets in $\R$ defined in the generalized Cantor and Baire spaces ($2^\kappa$ and $\kappa^\kappa$). We consider generalizations of the well-known classes of…

Logic · Mathematics 2020-03-03 Michał Korch , Tomasz Weiss

We strengthen the property $\Delta$ of a function $f:[\omega_2]^2\rightarrow [\omega_2]^{\leq \omega}$ considered by Baumgartner and Shelah. This allows us to consider new types of amalgamations in the forcing used by Rabus, Juh\'asz and…

Functional Analysis · Mathematics 2010-09-17 Christina Brech , Piotr Koszmider

We show in detail that every compact countable subset of a metric space is homeomorphic to a countable ordinal number, which extends a result given by Mazurkiewicz and Sierpinski for finite-dimensional Euclidean spaces. In order to achieve…

General Topology · Mathematics 2019-11-12 Borys Álvarez-Samaniego , Andrés Merino

K. Kuperberg found a locally connected, finite-dimensional continuum which is homogeneous but not bihomogeneous. We give a similar but simpler example. Like previous constructions, the example is locally a Cartesian product of Menger…

General Topology · Mathematics 2007-05-23 Greg Kuperberg

We improve previous work on the consistency strength of mutually stationary sequences of sets concentrating on points with divergent cofinality building on previous work by Adolf, Cox and Welch. Specifically, we have greatly reduced our…

Logic · Mathematics 2019-08-06 Dominik Adolf