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One of the prime motivation for topology was Homotopy theory, which captures the general idea of a continuous transformation between two entities, which may be spaces or maps. In later decades, an algebraic formulation of topology was…

Category Theory · Mathematics 2025-11-24 Suddhasattwa Das

Given a torus action on a compact space X, a fundamental result of Borel and Atiyah-Segal asserts that the equivariant cohomology of X is concentrated in the fixed locus X^T, up to inverting enough Chern classes. We prove an analogue for…

Algebraic Geometry · Mathematics 2023-08-04 Adeel A. Khan , Charanya Ravi

Motivated by the theory of representability classes by submanifolds, we study the rational homotopy theory of Thom spaces of vector bundles. We first give a Thom isomorphism at the level of rational homotopy, extending work of…

Algebraic Topology · Mathematics 2017-08-23 Urtzi Buijs , Federico Cantero Morán , Joana Cirici

Our main result states that for each finite complex L the category ${\bf TOP}$ of topological spaces possesses a model category structure (in the sense of Quillen) whose weak equivalences are precisely maps which induce isomorphisms of all…

Algebraic Topology · Mathematics 2007-05-23 A. Chigogidze , A. Karasev

We compare two models for $\infty$-operads: the complete Segal operads of Barwick and the complete dendroidal Segal spaces of Cisinski and Moerdijk. Combining this with comparison results already in the literature, this implies that all…

Algebraic Topology · Mathematics 2020-11-03 Hongyi Chu , Rune Haugseng , Gijs Heuts

Pseudotopological spaces are the Cartesian closed hull of the category of \v{C}ech closure spaces. In this paper, we give a direct proof that the model category of the pseudotopological spaces constructed by Rieser is Quillen equivalent to…

Algebraic Topology · Mathematics 2025-10-22 Jonathan Treviño-Marroquín

The Dold$-$Thom theorem states that for a sufficiently nice topological space, M, there is an isomorphism between the homotopy groups of the infinite symmetric product of M and the homology groups of M itself. The crux of most known proofs…

Algebraic Topology · Mathematics 2017-08-08 Lauren Bandklayder

We prove that any complex or real analytic set or function germ is topologically equivalent to a germ defined by polynomial equations whose coefficients are algebraic numbers.

Algebraic Geometry · Mathematics 2018-08-08 Guillaume Rond

We identify the cohomology of the stable classifying space of homotopy automorphisms (relative to an embedded disk) of connected sums of $S^k \times S^l$, where $3 \le k < l \le 2k - 2$. The result is expressed in terms of Lie graph complex…

Algebraic Topology · Mathematics 2024-03-19 Robin Stoll

The goal of this paper is to prove an equivalence between the model categorical approach to pro-categories, as studied by Isaksen, Schlank and the first author, and the $\infty$-categorical approach, as developed by Lurie. Three…

Algebraic Topology · Mathematics 2017-02-01 Ilan Barnea , Yonatan Harpaz , Geoffroy Horel

In this paper we study a new notion of category weight of homology classes developing further the ideas of E. Fadell and S. Husseini. In the case of closed smooth manifolds the homological category weight is equivalent to the cohomological…

Algebraic Topology · Mathematics 2016-09-07 Michael Farber , Dirk Schuetz

We develop a class of homeomorphisms on a compact homogeneous space of a transitive group action and show how the class sheds new light on a decomposition problem. We further use this class to show that every such homogeneous space in a…

Functional Analysis · Mathematics 2023-08-22 Samuel A. Hokamp

We give an interpretation of holography in the form of the AdS/CFT correspondence in terms of homotopy algebras. A field theory such as a bulk gravity theory can be viewed as a homotopy Lie or $L_{\infty}$ algebra. We extend this dictionary…

High Energy Physics - Theory · Physics 2023-09-08 Christoph Chiaffrino , Talha Ersoy , Olaf Hohm

This thesis is divided into two parts. In the first part, we study models of $(\infty,\omega)$-categories. The main result is to establish a Quillen equivalence between Rezk's complete Segal $\Theta$-spaces and Verity's complicial sets. In…

Category Theory · Mathematics 2023-10-13 Félix Loubaton

This paper gives a uniform-theoretic refinement of classical homotopy theory. Both cubical sets (with connections) and uniform spaces admit classes of weak equivalences, special cases of classical weak equivalences, appropriate for the…

Algebraic Topology · Mathematics 2021-09-20 Sanjeevi Krishnan , Crichton Ogle

We discuss a new point of view of representation theory of Lie groupoids and algebroids: fat Lie theory. The category of fat extensions is introduced, as well as the category of abstract $2$-term representations up to homotopy (ruths) --…

Differential Geometry · Mathematics 2026-05-15 Lennart Obster

We show that a locally symmetric space of noncompact type and with finite volume is quasi-isometric to the euclidean cone over a finite simplicial complex. A detailed analysis of metric properties yields a proof of a conjecture of Siegel.

Differential Geometry · Mathematics 2007-05-23 E. Leuzinger

In this paper, we justify and make precise an elementary approach that establishes the existence of (co)limits in $\mathbf{Cat}$. This approach, while conceptually evident, has not been made fully explicit or systematically described in the…

Category Theory · Mathematics 2026-04-16 Varinderjit Mann

In this short note we show that the homotopy category of smooth compactifications of smooth algebraic varieties is equivalent to the homotopy category of smooth varieties over a field of characteristic zero. As an application we show that…

Algebraic Geometry · Mathematics 2013-09-03 Gereon Quick

The notion of conformal algebras was introduced by Victor G. Kac using the axiomatic description of the operator product expansion of chiral fields in conformal field theory. The structure theory, representations and cohomology of Lie and…

Rings and Algebras · Mathematics 2023-10-02 Anupam Sahoo , Apurba Das