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Related papers: Extension of Hyperspace Selections

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We consider two basic problems of algebraic topology, the extension problem and the computation of higher homotopy groups, from the point of view of computability and computational complexity. The extension problem is the following: Given…

Computational Geometry · Computer Science 2013-02-12 Martin Cadek , Marek Krcal , Jiri Matousek , Lukas Vokrinek , Uli Wagner

This document is the Ph.D. thesis of Leonard Parker, submitted to Harvard University in 1966. Over the decades, several generations of physicists have been introduced to the concept of particle creation by gravitational fields, a phenomenon…

General Relativity and Quantum Cosmology · Physics 2025-07-09 Leonard E. Parker

A homological selection theorem for C-spaces, as well as, a finite-dimensional homological selection theorem is established. We apply the finite-dimensional homological selection theorem to obtain fixed-point theorems for usco homologically…

General Topology · Mathematics 2017-02-14 Vesko Valov

We study Michael's lower semifinite topology and Fell's topology on the collection of all closed limit subsets of a topological space. Special attention is given to the subfamily of all maximal limit sets.

General Topology · Mathematics 2008-11-21 Aldo J. Lazar

The paper contains an exposition of recent as well as old enough results on determinantal random point fields. We start with some general theorems including the proofs of the necessary and sufficient condition for the existence of the…

Probability · Mathematics 2015-06-26 Alexander Soshnikov

See hep-ph/0304045

General Relativity and Quantum Cosmology · Physics 2007-05-23 Ramy Naboulsi

We give a light introduction to selection principles in topology, a young subfield of infinite-combinatorial topology. Emphasis is put on the modern approach to the problems it deals with. Recent results are described, and open problems are…

General Topology · Mathematics 2010-11-02 Boaz Tsaban

In this paper we discuss various philosophical aspects of the hyperstructure concept extending networks and higher categories. By this discussion we hope to pave the way for applications and further developments of the mathematical theory…

General Mathematics · Mathematics 2015-12-02 Nils A. Baas

In this paper we address the decision problem for a fragment of set theory with restricted quantification which extends the language studied in [4] with pair related quantifiers and constructs, in view of possible applications in the field…

Logic in Computer Science · Computer Science 2012-10-10 Domenico Cantone , Cristiano Longo

Characterizations of paracompact finite $C$-spaces via continuous selections are given. We apply these results to obtain some properties of finite $C$-spaces. Factorization theorems and a completion theorem for finite $C$- spaces are also…

General Topology · Mathematics 2016-09-07 Vesko Valov

Isaak Moiseevich Yaglom deduced complete classification of geometric spaces. In this work, supposed to your attention, author formalizes Yaglom's approach and constructs uniform theory of geometric spaces on analytic level. Among its…

Metric Geometry · Mathematics 2018-07-31 Alexander Popa

After mathematicians and physicists had learned that the structure of physical space was not necessarily Euclidean, it became conceivable that the global topological structure of space was non-trivial. In the context of the late 19th…

History and Overview · Mathematics 2007-05-23 Moritz Epple

The expansion of the closed two-component universe has been considered. The potential barrier of the expansion has been investigated and its overcoming condition has been obtained. The restrictions on the Friedmann integrals, cosmological…

General Relativity and Quantum Cosmology · Physics 2009-09-29 O. B. Karpov

The kinematics and dynamic interpretation of the cosmological expansion is reviewed in a widely accessible manner with emphasis on the acceleration aspect. Virtually all the approaches that can in principle account for the accelerated…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-19 Yu. L. Bolotin , O. A. Lemets , D. A. Yerokhin

In this paper we solve the polarization problem for real Hilbert spaces, a long-standing conjecture that had remained open for nearly three decades. We also confirm that the only extremal configurations are orthonormal sets. These are…

Functional Analysis · Mathematics 2026-05-28 Ángel D. Martínez , Oscar Ortega-Moreno

In a recent paper, it was shown that the problem of existence of a continuous map $X \to Y$ extending a given map $A \to Y$ defined on a subspace $A \subseteq X$ is undecidable, even for $Y$ an even-dimensional sphere. In the present paper,…

Algebraic Topology · Mathematics 2014-01-17 Lukáš Vokřínek

The German-born astronomer Jacob K. E. Halm (1866-1944) wrote in 1935 two papers on quite different subjects, one an astrophysically based argument for the expanding Earth and the other a no less original attempt to explain the galactic…

History and Philosophy of Physics · Physics 2015-07-30 Helge Kragh

Michael's selection theorem implies that a closed convex nonempty-valued mapping from the Sorgenfrey line to a euclidean space is inner semicontinuous if and only if the mapping can be represented as the image closure of right-continuous…

Optimization and Control · Mathematics 2022-04-12 Ari-Pekka Perkkiö , Erick Treviño-Aguilar

Recently, a novel idea about our expanding Universe was proposed by T. Padmanabhan [arXiv:1206.4916]. He suggested that the expansion of our Universe can be thought of as the emergence of space as cosmic time progresses. The emergence is…

High Energy Physics - Theory · Physics 2012-11-13 Ke Yang , Yu-Xiao Liu , Yong-Qiang Wang

While it remains the staple of virtually all cosmological teaching, the concept of expanding space in explaining the increasing separation of galaxies has recently come under fire as a dangerous idea whose application leads to the…

Astrophysics · Physics 2009-03-19 Matthew J. Francis , Luke A. Barnes , J. Berian James , Geraint F. Lewis