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Spectral Method is a commonly used scheme to cluster data points lying close to Union of Subspaces by first constructing a Random Geometry Graph, called Subspace Clustering. This paper establishes a theory to analyze this method. Based on…

Machine Learning · Computer Science 2019-07-26 Gen Li , Yuantao Gu

The set of all closed subgroups of a profinite carries a natural profinite topology. This space of subgroups can be classified up to homeomorphism in many cases, and tight bounds placed on its complexity as expressed by its scattered…

Group Theory · Mathematics 2008-09-30 Paul Gartside , Michael Smith

We introduce and study the class of spherically ordered groups. The notions of spherically ordered groups and their spectra of spherical orderability are introduced. Values of these spectra are found for a series of natural groups.

Group Theory · Mathematics 2024-07-19 Sergey V. Sudoplatov

These notes give a brief introduction to the category of spectra as defined in stable homotopy theory. In particular, Section 5 discusses an extensive list of examples of spectra whose properties have been found to be interesting.

Algebraic Topology · Mathematics 2020-01-29 Neil Strickland

Using a new definition of a prime ideal of a skew brace A, on set Spec A of prime ideals of A we endow a spectral topology (in the sense of Grothendieck). We characterize irreducible closed subsets of Spec A and prove every irreducible…

Rings and Algebras · Mathematics 2025-04-29 Themba Dube , Amartya Goswami

Various spectral notions have been employed to grasp the structure of point sets, in particular non-periodic ones. In this article, we present them in a unified setting and explain the relations between them. For the sake of readability, we…

Dynamical Systems · Mathematics 2017-02-21 Michael Baake , Daniel Lenz

In this article we develop the cotangent complex and (co)homology theories for spectral categories. Along the way, we reproduce standard model structures on spectral categories. As applications, we show that the invariants to descend to…

Algebraic Topology · Mathematics 2015-12-24 Jonathan A. Campbell

The notion of a coherent space is a nonlinear version of the notion of a complex Euclidean space: The vector space axioms are dropped while the notion of inner product is kept. Coherent spaces provide a setting for the study of geometry in…

Mathematical Physics · Physics 2018-10-01 Arnold Neumaier

We already saw in [A1] that the space of dynamically marked rational maps can be identified to a subspace of the space of covers between trees of spheres on which there is a notion of convergence that makes it sequentially compact. In the…

Dynamical Systems · Mathematics 2017-09-15 Matthieu Arfeux

A space $X$ is called $CCS$-normal space if there exist a normal space $Y$ and a bijection $f: X\mapsto Y$ such that $f\lvert_C:C\mapsto f(C)$ is homeomorphism for any cellular-compact subset $C$ of $X$. We discuss about the relations…

General Topology · Mathematics 2020-07-14 Sagarmoy Bag , Ram Chandra Manna , Asit Baran Raha

The notion of a spectral geometry on a compact metric space X is introduced. This notion serves as a discrete approximation of X motivated by the notion of a spectral triple from non-commutative geometry. A set of axioms charaterising…

Operator Algebras · Mathematics 2017-11-01 Sergei Buyalo

We introduce the notion of a "graded topological space": a topological space endowed with a sheaf of abelian groups which we think of as a sheaf of gradings. Any object living on a graded topological space will be graded by this sheaf of…

Algebraic Geometry · Mathematics 2020-07-20 Clemens Koppensteiner

The aim of this paper is twofold. Firstly, we give easy-to-handle criteria to determine whether a given family of subsets of a vector space is a neighbourhood basis of the origin for a complete vector topology. Then, we apply these criteria…

Functional Analysis · Mathematics 2025-02-20 José L. Ansorena , Alejandro Marcos

The article is devoted to a structure of topological spaces related with topological quasigroups. Regular and complete spaces over topological quasigroups are studied. Separations and embeddings are also investigated for them. Their…

Group Theory · Mathematics 2023-12-29 S. V. Ludkowski

The aim of this note is to prove that the parabolic closure of any subset of a Coxeter group is a parabolic subgroup. To obtain that, several technical lemmas on the root system of a parabolic subgroup are established.

Group Theory · Mathematics 2007-05-23 Dongwen Qi

A paratopological group $G$ has a {\it suitable set} $S$. The latter means that $S$ is a discrete subspace of $G$, $S\cup \{e\}$ is closed, and the subgroup $\langle S\rangle$ of $G$ generated by $S$ is dense in $G$. Suitable sets in…

General Topology · Mathematics 2020-12-25 Fucai Lin , Alex Ravsky , Tingting Shi

We prove that closed manifolds admitting a generic metric whose sectional curvature is locally quasi-constant are graphs of space forms. In the more general setting of QC spaces where sets of isotropic points are arbitrary, under suitable…

Differential Geometry · Mathematics 2020-04-08 Louis Funar

Let $X$ be the prime spectrum of a ring. In [arXiv:0707.1525] the authors define a topology on $X$ by using ultrafilters and they show that this topology is precisely the constructible topology. In this paper we generalize the construction…

Commutative Algebra · Mathematics 2013-09-23 Carmelo A. Finocchiaro

Let X be a definable sub-set of some o-minimal structure. We study the spectrum of X, in relation with the definability of types.

Logic · Mathematics 2007-05-23 Antongiulio Fornasiero

A bounded set $\Omega \subset \mathbb{R}^d$ is called a spectral set if the space $L^2(\Omega)$ admits a complete orthogonal system of exponential functions. We prove that a cylindric set $\Omega$ is spectral if and only if its base is a…

Classical Analysis and ODEs · Mathematics 2016-09-26 Rachel Greenfeld , Nir Lev