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We define here the category of partial differential equations. Special cases of morphisms from an object (equation) are symmetries of the equation and reductions of the equation by a symmetry groups, but there are many other morphisms. We…

Analysis of PDEs · Mathematics 2009-05-29 Marina Prokhorova

Various concerns suggest looking for internal co-categories in categories with strong logical structure. It turns out that in any coherent category, all co-categories are co-equivalence relations.

Category Theory · Mathematics 2014-11-21 Peter LeFanu Lumsdaine

Given two schemes $S$ and $S'$, we prove that every equivalence between $\mathbf{Sch}_S$ and $\mathbf{Sch}_{S'}$ comes from a unique isomorphism between $S$ and $S'$. This eliminates all Noetherian and finite type hypotheses from a result…

Algebraic Geometry · Mathematics 2019-06-04 Remy van Dobben de Bruyn

Algebra objects in $\infty$-categories of spans admit a description in terms of $2$-Segal objects. We introduce a notion of span between $2$-Segal objects and extend this correspondence to an equivalence of $\infty$-categories.…

Algebraic Topology · Mathematics 2025-10-30 Jonte Gödicke

We define notions of generically and coarsely computable relations and structures and functions between structures. We investigate the existence and uniqueness of equivalence structures in the context of these definitions

Logic · Mathematics 2018-08-09 Wesley Calvert , Douglas Cenzer , Valentina Harizanov

In this note we remark on the problem of equality of objects in categories formalized in Martin-L\"of's constructive type theory. A standard notion of category in this system is E-category, where no such equality is specified. The main…

Category Theory · Mathematics 2019-09-17 Erik Palmgren

Category theory in homotopy type theory is intricate as categorical laws can only be stated "up to homotopy", and thus require coherences. The established notion of a univalent category (Ahrens, Kapulkin, Shulman) solves this by considering…

Category Theory · Mathematics 2017-10-31 Paolo Capriotti , Nicolai Kraus

We show that for a given exact category, there exists a bijection between semibricks (pairwise Hom-orthogonal set of bricks) and length wide subcategories (exact extension-closed length abelian subcategories). In particular, we show that a…

Category Theory · Mathematics 2022-08-08 Haruhisa Enomoto

Constructions of spectra from symmetric monoidal categories are typically functorial with respect to strict structure-preserving maps, but often the maps of interest are merely lax monoidal. We describe conditions under which one can…

Algebraic Topology · Mathematics 2017-09-26 Nick Gurski , Niles Johnson , Angélica M. Osorno

The notion of right semi-equivalence in a right $(n+2)$-angulated category is defined in this article. Let $\mathscr C$ be an $n$-exangulated category and $\mathscr X$ is a strongly covariantly finite subcategory of $\mathscr C$. We prove…

Representation Theory · Mathematics 2021-08-19 Jian He , Panyue Zhou

The work argues the principle of equivalence to be a theorem and not a principle (in a sense of an axiom). It contains a detailed analysis of the concepts of normal and inertial frame of reference. The equivalence principle is proved to be…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Bozhidar Z. Iliev

Linear categories naturally have several identification relations : isomorphisms, categorical equivalences and Morita equivalences. In this thesis, we construct the classifying stacks for these three relations ($\ukcatiso$, $\ukcateq$,…

Algebraic Geometry · Mathematics 2007-05-23 Mathieu Anel

It is well-known that biological phenomena are emergent. Emergent phenomena are quite interesting and amazing. However, they are difficult to be understood. Due to this difficulty, we propose a theory to describe emergence based on a…

Category Theory · Mathematics 2018-10-30 Giuliano Gadioli La Guardia , Pedro Jeferson Miranda

We prove a bicategorical analogue of Quillen's Theorem A. As an application, we deduce the well-known result that a pseudofunctor is a biequivalence if and only if it is essentially surjective on objects, essentially full on 1-cells, and…

Category Theory · Mathematics 2021-12-21 Niles Johnson , Donald Yau

In the paper the main attention is paid to conditions on algebras from a given variety which provide coincidence of their algebraic geometries. The main part here play the notions mentioned in the title of the paper.

General Mathematics · Mathematics 2007-05-23 B. Plotkin

Classically, there are two model category structures on coalgebras in the category of chain complexes over a field. In one, the weak equivalences are maps which induce an isomorphism on homology. In the other, the weak equivalences are maps…

Algebraic Topology · Mathematics 2015-05-26 Gabriel C. Drummond-Cole , Joseph Hirsh

It is known that a countable $\omega$-categorical structure interprets all finite structures primitively positively if and only if its polymorphism clone maps to the clone of projections on a two-element set via a continuous clone…

Logic · Mathematics 2023-06-22 Manuel Bodirsky , Michael Pinsker , András Pongrácz

Coherence is here demonstrated for sesquicartesian categories, which are categories with nonempty finite products and arbitrary finite sums, including the empty sum, where moreover the first and the second projection from the product of the…

Category Theory · Mathematics 2007-05-23 K. Dosen , Z. Petric

The Hecke category is bigraded. For completeness, we classify gradings on the Hecke category. We also classify object-preserving autoequivalences.

Representation Theory · Mathematics 2023-05-16 Ben Elias

This is mostly an overview. Given finitely presentable abelian categories $A$ and $B$, we sketch the construction of an abelian category of continuous functors from $A$ to $B$ that has nice $2$-categorical behaviour and gives an explicit…

Category Theory · Mathematics 2022-05-18 D. Kaledin