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For a topologically complete space $X$ and a family of closed covers $\mathcal A$ of $X$ satisfying a "local refinement condition" and a "completeness condition," we give a construction of an inverse system $\mathbf{ N}_{\mathcal A}$ of…

General Topology · Mathematics 2019-07-29 Wojciech Dębski , Kazuhiro Kawamura , Murat Tuncalı , E. D. Tymchatyn

Let $X$ be a quasi-affine algebraic variety isomorphic to the complement of a closed subvariety of dimension at most $n-3$ in $\C^n$. We find some conditions under which an isomorphism of two closed subvarieties of $X$ can be extended to an…

Algebraic Geometry · Mathematics 2018-12-03 Shulim Kaliman

We show how to extend a metric defined on the vertex set of a simplicial complex to the whole simplicial complex, thus correcting a mistake in Mineyev's construction of a flow space.

Algebraic Topology · Mathematics 2013-09-05 Adam Mole

In this paper, isometric embedding results of Greene, Gromov and Rokhlin are extended to what are called "indefinite metric polyhedra". Two definitions for an indefinite metric polyhedron are given, an intuitive definition and a more useful…

Metric Geometry · Mathematics 2015-08-06 Barry Minemyer

We prove the following Theorem: Let X be a nonempty compact metrizable space, let $l_1 \leq l_2 \leq...$ be a sequence of natural numbers, and let $X_1 \subset X_2 \subset...$ be a sequence of nonempty closed subspaces of X such that for…

Geometric Topology · Mathematics 2013-01-29 Leonard R. Rubin , Vera Tonić

Our main goal in this article is to prove a new extension theorem for sections of the canonical bundle of a weakly pseudoconvex K\"ahler manifold with values in a line bundle endowed with a possibly singular metric. We also give some…

Algebraic Geometry · Mathematics 2017-10-04 Junyan Cao

When finding an original proof to a known result describing expansive mappings on compact metric spaces as surjective isometries, we reveal that relaxing the condition of compactness to total boundedness preserves the isometry property and…

Functional Analysis · Mathematics 2019-10-24 Marat V. Markin , Edward S. Sichel

In this paper we extend recent results of Fiorini et al. on the extension complexity of the cut polytope and related polyhedra. We first describe a lifting argument to show exponential extension complexity for a number of NP-complete…

Combinatorics · Mathematics 2013-04-30 David Avis , Hans Raj Tiwary

We establish extension theorems for separately holomorphic mappings defined on sets of the form W\setminus M with values in a complex analytic space which possesses the Hartogs extension property. Here W is a 2-fold cross of arbitrary…

Complex Variables · Mathematics 2009-01-21 Viet-Anh Nguyen , Peter Pflug

An ultrametric defined on a subset S of a metric space X can be extended to X while roughly preserving distances between pairs in S x X.

Metric Geometry · Mathematics 2012-11-14 Manor Mendel

The aim of this paper is to show how the homotopy type of compact metric spaces can be reconstructed by the inverse limit of an inverse sequence of finite approximations of the corresponding space. This recovering allows us to define…

Geometric Topology · Mathematics 2018-02-28 Diego Mondéjar Ruiz , Manuel A. Morón

This work is devoted to the investigation of the problem about inverse mapping systems expansions of ultrauniform spaces $X$ using polyhedra over non-Archimedean locally compact fields $\bf L$. Theorems about expansions of complete…

Algebraic Topology · Mathematics 2007-05-23 S. V. Ludkovsky

We consider extensions of non-singular maps which are exact, respectively K-mixing, or at least have a decomposition into positive-measure exact, respectively K-mixing, components. The fibers of the extension spaces have countable (finite…

Dynamical Systems · Mathematics 2025-02-11 Daniele Galli , Marco Lenci

This paper studies Moore's measurable cohomology theory for locally compact groups and Polish modules. An elementary dimension-shifting argument is used to show that all classes in that theory have representatives with considerable extra…

Group Theory · Mathematics 2012-06-14 Tim Austin

The main result of this paper is the extension of the Schur-Horn Theorem to infinite sequences: For two nonincreasing nonsummable sequences x and y that converge to 0, there exists a compact operator A with eigenvalue list y and diagonal…

Operator Algebras · Mathematics 2009-05-22 Victor Kaftal , Gary Weiss

We show in ZF that: (i) Every subcompact metrizable space is completely metrizable, and every completely metrizable space is countably subcompact. (ii) A metrizable space X=(X,T) is countably compact iff it is countably subcompact relative…

General Topology · Mathematics 2021-02-23 Kyriakos Keremedis

We extend the definition of weak and strong convergence to sequences of Sobolev-functions whose underlying domains themselves are converging. In contrast to previous works, we do so without ever assuming any sort of reference configuration.…

Analysis of PDEs · Mathematics 2024-11-20 Nikita Evseev , Malte Kampschulte , Alexander Menovschikov

It is known that any two triangulations of a compact 3-manifold are related by finite sequences of certain local transformations. We prove here an upper bound for the length of a shortest transformation sequence relating any two…

Geometric Topology · Mathematics 2007-05-23 Simon A. King

Ends and end cohomology are powerful invariants for the study of noncompact spaces. We present a self-contained exposition of the topological theory of ends and prove novel extensions including the existence of an exhaustion of a proper…

Algebraic Topology · Mathematics 2025-04-17 William G. Bass , Jack S. Calcut

We propose the extension of the complex numbers to be the new domain where new concepts, like negative and imaginary probabilities, can be defined. The unit of the new space is defined as the solution of the unsolvable equation in the…

General Physics · Physics 2020-12-03 Israel Ariel González Medina