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We prove some generalizations of results concerning Valdivia compact spaces (equivalently spaces with a commutative retractional skeleton) to the spaces with a retractional skeleton (not necessarily commutative). Namely, we show that the…

Functional Analysis · Mathematics 2014-01-30 Marek Cuth

We study compact spaces which are obtained from metric compacta by iterating the operation of inverse limit of continuous sequences of retractions. We denote this class by R. Allowing continuous images in the definition of class R, one…

General Topology · Mathematics 2012-10-23 Wieslaw Kubis

The aim of this note is to characterize trees, endowed with coarse wedge topology, that have a retractional skeleton. We use this characterization to provide new examples of non-commutative Valdivia compact spaces that are not Valdivia.

General Topology · Mathematics 2018-03-07 Jacopo Somaglia

We give a new characterization of Valdivia compact spaces: A compact space is Valdivia if and only if it has a dense commutatively monotonically retractable subspace. This result solves Problem 5.12 from \cite{sal-rey}. Besides, we…

General Topology · Mathematics 2016-07-04 F. Casarrubias-Segura , S. García-Ferreira , R. Rojas-Hernández

We prove a preservation theorem for the class of Valdivia compact spaces, which involves inverse sequences of ``simple'' retractions. Consequently, a compact space of weight $\loe\aleph_1$ is Valdivia compact iff it is the limit of an…

General Topology · Mathematics 2012-10-23 Wieslaw Kubiś , Henryk Michalewski

We deeply study retractions associated to suitable models in compact spaces admitting a retractional skeleton and find several interesting consequences. Most importantly, we provide a new characterization of Valdivia compacta using the…

General Topology · Mathematics 2022-02-03 Claudia Correa , Marek Cúth , Jacopo Somaglia

Assuming that there is a stationary set in $\omega_{2}$ of ordinals of countable cofinality that does not reflect, we prove that there exists a compact space which is not Corson compact and whose all continuous images of weight at most…

General Topology · Mathematics 2016-08-09 Menachem Magidor , Grzegorz Plebanek

An $r$-skeleton on a compact space is a family of continuous retractions having certain rich properties. The $r$-skeletons have been used to characterized the Valdivia compact spaces and the Corson compact spaces. Here, we characterized a…

General Topology · Mathematics 2018-04-06 S. Garcia-Ferreira , C. Yescas-Aparicio

The class of Hausdorff spaces that are continuous images of compact orderable spaces is studied by analyzing the relationship between the elements of this class and compact orderable spaces in a back-and-forth fashion. Structure results for…

General Topology · Mathematics 2016-11-15 Ahmad Farhat

A compact space is said to be weakly Radon-Nikod\'ym if it is homeomorphic to a weak*-compact subset of the dual of a Banach space not containing an isomorphic copy of $\ell_1$. In this work we provide an example of a continuous image of a…

Functional Analysis · Mathematics 2015-09-18 Gonzalo Martínez-Cervantes

We investigate the class of compact spaces which are embeddable into a power of the real line $R^\kappa$ in such a way that c_0(\kappa) is dense in the image. We show that this is a proper subclass of the class of Valdivia, even when…

General Topology · Mathematics 2012-10-23 W. Kubiś , A. Leiderman

Given a compact space in a fixed universe of set theory, one can naturally define its interpretation in any ZFC extension of the universe. We investigate the stability of some classes of compact spaces with respect to extensions of this…

General Topology · Mathematics 2014-02-10 Wiesław Kubiś

It is know that the Valdivia compact spaces can be characterized by a special family of retractions called $r$-skeleton (see \cite{kubis1}). Also we know that there are compact spaces with $r$-skeletons which are not Valdivia. In this…

General Topology · Mathematics 2020-01-20 S. Garcia-Ferreira , C. Yescas Aparicio

We introduce and study a new topology on trees, that we call the countably coarse wedge topology. Such a topology is strictly finer than the coarse wedge topology and it turns every chain complete, rooted tree into a Fr\'echet--Urysohn,…

General Topology · Mathematics 2022-03-16 Tommaso Russo , Jacopo Somaglia

We consider noncommutative theory of a compact scalar field. The recently discovered projector solitons are interpreted as classical vacua in the model considered. Localized solutions to the projector equation are pointed out and their…

High Energy Physics - Theory · Physics 2009-10-31 A. S. Gorsky , Y. M. Makeenko , K. G. Selivanov

We provide a characterization of continuous images of Radon-Nikodym compacta lying in a product of real lines and model on it a method for constructing natural examples of such continuous images.

General Topology · Mathematics 2010-01-26 Alexander D. Arvanitakis , Antonio Avilés

A reflection principle for Corson compacta holds in the forcing extension obtained by Levy-collapsing a supercompact cardinal to~$\aleph_2$. In this model, a compact Hausdorff space is Corson if and only if all of its continuous images of…

Logic · Mathematics 2020-01-28 Ilijas Farah , Menachem Magidor

We study linearly ordered spaces which are Valdivia compact in their order topology. We find an internal characterization of these spaces and we present a counter-example disproving a conjecture posed earlier by the first author. The…

General Topology · Mathematics 2012-10-23 Ondrej Kalenda , Wieslaw Kubis

A compact space $K$ is {\em Valdivia compact} if it can be embedded in a Tikhonov cube $I^A$ in such a way that the intersection $K\cap\Sigma$ is dense in $K$, where $\Sigma$ is the sigma-product (= the set of points with countably many…

General Topology · Mathematics 2012-10-23 Wieslaw Kubiś , Vladimir Uspenskij

We prove that a countably compact space is monotonically retractable if and only if it has a full retractional skeleton. In particular, a compact space is monotonically retractable if and only if it is Corson. This gives an answer to a…

General Topology · Mathematics 2014-11-07 Marek Cúth , Ondřej F. K. Kalenda
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