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The paper is the survey of the modern results and applications of the theory of homotopes. The notion of a well-tempered element in an associative algebra is introduced and it is proven that the category of representations of the homotope…

Representation Theory · Mathematics 2021-08-11 Alexey Bondal , Ilya Zhdanovskiy

We establish a bi-equivalence between the bi-category of topoi with enough points and a localisation of a bi-subcategory of topological groupoids

Category Theory · Mathematics 2026-03-17 Joshua Wrigley

It is a well-known fact that although the poset of open sets of a topological space is a Heyting algebra, its Heyting implication is not necessarily stable under the inverse image of continuous functions and hence is not a geometric…

Logic · Mathematics 2024-05-09 Amirhossein Akbar Tabatabai

A subunit in a monoidal category is a subobject of the monoidal unit for which a canonical morphism is invertible. They correspond to open subsets of a base topological space in categories such as those of sheaves or Hilbert modules. We…

Category Theory · Mathematics 2020-06-22 Pau Enrique Moliner , Chris Heunen , Sean Tull

Generalized topological spaces in the sense of Cs\'{a}sz\'{a}r have two main features which distinguish them from typical topologies. First, these families of subsets are not closed under intersections. Second, we allow for the possibility…

Logic · Mathematics 2019-09-23 Tomasz Witczak

For all classical groups (and for their analogs in infinite dimension or over general base fields or rings) we construct certain contractions, called "homotopes". The construction is geometric, using as ingredient involutions of associative…

Rings and Algebras · Mathematics 2010-05-19 Wolfgang Bertram , Michael Kinyon

For all classical groups (and for their analogs in infinite dimension or over general base fields or rings) we construct certain contractions, called "homotopes". The construction is geometric, using as ingredient involutions of associative…

Rings and Algebras · Mathematics 2010-05-31 Wolfgang Bertram , Michael Kinyon

This is the first in a series of papers devoted to foundations of topological stacks. We begin developing a homotopy theory for topological stacks along the lines of classical homotopy theory of topological spaces. In this paper we go as…

Algebraic Geometry · Mathematics 2007-05-23 Behrang Noohi

We introduce the notion of $n$-pure geometric morphism between Grothendieck toposes, over a Grothendieck base topos $\mathcal{T}$. This is a higher-dimensional analogue of the concepts of dense and pure geometric morphism. We extend the…

Category Theory · Mathematics 2025-10-14 Jens Hemelaer

A classical result of topos theory holds that the category of coalgebras for a Cartesian comonad on a topos is again a topos (Kock and Wraith, 1971). It is natural to refine this result to a topos-theoretic setting that includes universes.…

Category Theory · Mathematics 2024-05-02 Colin Zwanziger

End-spaces of infinite graphs naturally generalise the Freudenthal boundary and sit at the interface between graph theory, geometric group theory and topology. Our main result is that every end-space can topologically be represented by a…

Combinatorics · Mathematics 2024-09-02 Jan Kurkofka , Max Pitz

It has been shown by J.Funk, P.Hofstra and B.Steinberg that any Grothendieck topos T is endowed with a canonical group object, called its isotropy group, which acts functorially on every object of T. We show that this group is in fact the…

Category Theory · Mathematics 2017-06-16 Simon Henry

We present a sheaf-theoretic construction of shape space -- the space of all shapes. We do this by describing a homotopy sheaf on the poset category of constructible sets, where each set is mapped to its Persistent Homology Transform (PHT).…

Algebraic Topology · Mathematics 2023-06-26 Shreya Arya , Justin Curry , Sayan Mukherjee

The construction of manifold structures and fundamental classes on the (compactified) moduli spaces appearing in Gromov-Witten theory is a long-standing problem. Up until recently, most successful approaches involved the imposition of…

Symplectic Geometry · Mathematics 2014-05-27 Andreas Gerstenberger

Connections between heaps of modules and (affine) modules over rings are explored. This leads to explicit, often constructive, descriptions of some categorical constructions and properties that are implicit in universal algebra and…

Rings and Algebras · Mathematics 2025-10-08 Simion Breaz , Tomasz Brzezinski , Bernard Rybolowicz , Paolo Saracco

We discuss how canonical and universal constructions, properties and characterizations interact with equality in the framework of Homotopy Type Theory, comparing it with Grothendieck's use of equality and shedding further light on…

Logic · Mathematics 2026-04-02 Thomas Eckl

The aim of this paper is to prove the statement in the title. As a by-product, we obtain new globalization results in cases never considered before, such as partial corepresentations of Hopf algebras. Moreover, we show that for partial…

Rings and Algebras · Mathematics 2023-09-11 Paolo Saracco , Joost Vercruysse

Finite \'etale covers of a connected scheme $X$ are parametrised by the \'etale fundamental group via the monodromy correspondence. This was generalised to an exodromy correspondence for constructible sheaves, first in the topological…

Algebraic Geometry · Mathematics 2024-10-10 Remy van Dobben de Bruyn

We define general notions of coordinate geometries over fields and ordered fields, and consider coordinate geometries that are given by finitely many relations that are definable over those fields. We show that the automorphism group of…

Logic · Mathematics 2025-07-15 Judit Madarász , Mike Stannett , Gergely Székely

The first part of this dissertation defines "dependently typed algebraic theories", which are a strict subclass of the generalised algebraic theories (GATs) of Cartmell. We characterise dependently typed algebraic theories as finitary…

Category Theory · Mathematics 2021-10-07 Chaitanya Leena Subramaniam
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