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We construct a complete locally convex topological vector space $X$ of countable algebraic dimension and a continuous linear operator $T:X\to X$ such that $T$ has no non-trivial closed invariant subspaces.

Functional Analysis · Mathematics 2010-09-15 Stanislav Shkarin

We develop a generalized covering space theory for a class of uniform spaces called coverable spaces. Coverable spaces include all geodesic metric spaces, connected and locally pathwise connected compact topological spaces, in particular…

Algebraic Topology · Mathematics 2007-05-23 Valera Berestovskii , Conrad Plaut

We compute the completion of the local ring of the Hilbert scheme of degree $n+1$ subschemes of $\mathbb{A}^n$ at the point corresponding to the ideal $\langle x_1,\ldots,x_n\rangle^2$, and describe the completion of the universal family.…

Algebraic Geometry · Mathematics 2025-10-24 Nathan Ilten , Francesco Meazzini , Andrea Petracci

Local properties of the fundamental group of a path-connected topological space can pose obstructions to the applicability of covering space theory. A generalized covering map is a generalization of the classical notion of covering map…

Algebraic Topology · Mathematics 2020-04-14 Jeremy Brazas , Hanspeter Fischer

The topology of a space $X$ is generated by a family $\mathcal{C}$ of its subsets provided that a set $A\subseteq X$ is closed in $X$ if and only if $A\cap C$ is closed in $C$ for each $C\in \mathcal{C}$. A space $X$ is a $k$-space…

General Topology · Mathematics 2025-09-09 Ziqin Feng , Paul Gartside

We introduce the category of finite \'etale covers of an arbitrary schematic finite space $X$ and show that, equipped with an appropriate natural fiber functor, it is a Galois Category. This allows us to define the \'etale fundamental group…

Algebraic Geometry · Mathematics 2021-05-06 J. Sánchez González , C. Tejero Prieto

For a smooth quasi-projective surface $X$ and an integer $n\ge 3$, we show that the universal family $Z^n$ over the Hilbert scheme $\text{Hilb}^{n}(X)$ of $n$ points has non $\mathbb{Q}$-Gorenstein, rational singularities, and that the…

Algebraic Geometry · Mathematics 2015-09-25 Lei Song

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 $G$ be a simple and simply connected algebraic group over an algebraically closed field $\Bbbk$ of characteristic $p>0$. Assume that $p$ is good for the root system of $G$ and that the covering map $G_{sc} \rightarrow G$ is separable.…

Group Theory · Mathematics 2017-08-15 Paul Sobaje

We consider a finitely generated virtually abelian group $G$ acting properly and without inversions on a CAT(0) cube complex $X$. We prove that $G$ stabilizes a finite dimensional CAT(0) subcomplex $Y \subseteq X$ that is isometrically…

Group Theory · Mathematics 2018-03-16 Daniel J. Woodhouse

We provide a universal construction of the category of finite-dimensional C*-algebras and completely positive trace-nonincreasing maps from the rig category of finite-dimensional Hilbert spaces and unitaries. This construction, which can be…

Quantum Physics · Physics 2023-11-16 Pablo Andrés-MartíÂ-nez , Chris Heunen , Robin Kaarsgaard

We present the construction of an associative, commutative algebra $\hat {\mathcal G}$ of generalized functions on a manifold $X$ satisfying the following optimal set of permanence properties: (i)The space of distributions on $X$ is…

Functional Analysis · Mathematics 2007-05-23 Michael Kunzinger

We construct certain Hilbert spaces associated with a class of non-linear dynamical systems X. These are systems which arise from a generalized self-similarity, and an iterated substitution. We show that when a weight function W on X is…

Dynamical Systems · Mathematics 2007-05-23 Dorin Ervin Dutkay , Palle E. T. Jorgensen

For a metrizable space $X$, we denote by $\mathrm{Met}(X)$ the space of all metric that generate the same topology of $X$. The space $\mathrm{Met}(X)$ is equipped with the supremum distance. In this paper, for every strongly…

Metric Geometry · Mathematics 2023-04-20 Yoshito Ishiki

For any compact Lie group $G$ and any $n$ we construct a smooth $G$-manifold $U_n(G)$ such that any smooth $n$-dimensional $G$-manifold can be embedded in $U_n(G)$ with a trivial normal bundle. Furthermore, we show that such embeddings are…

Algebraic Topology · Mathematics 2025-01-03 Arthur G. Wasserman

In [1] we introduced the concept of structured space, which is a topological space that locally resembles some algebraic structures. In [2] we proceeded the study of these spaces, developing two cohomology theories. The aim of this paper is…

Algebraic Topology · Mathematics 2020-04-28 Manuel Norman

We strengthen, in various directions, the theorem of Garnett that every $\sigma$-compact, completely regular space $X$ occurs as a Gleason part for some uniform algebra. In particular, we show that the uniform algebra can always be chosen…

Complex Variables · Mathematics 2021-01-20 Alexander J. Izzo , Dimitris Papathanasiou

Let A be a linear space of operators on a Hilbert space H, x a vector in H, and Ax the subspace of H comprising all vectors of the form Tx with T in A. We discuss, within a Bishop-style constructive framework, conditions under which the…

Functional Analysis · Mathematics 2015-07-01 Douglas Suth Bridges

This article describes a structure that metric spaces can be equipped with so that they resemble normed vector spaces and examines necessary and sufficient conditions for the existence of such a structure on a general metric space.

Metric Geometry · Mathematics 2023-02-21 Ammar Hussain

Graded Hecke algebras can be constructed geometrically, with constructible sheaves and equivariant cohomology. The input consists of a complex reductive group G (possibly disconnected) and a cuspidal local system on a nilpotent orbit for a…

Algebraic Geometry · Mathematics 2025-01-20 Maarten Solleveld