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Diagrammatic sets admit a notion of internal equivalence in the sense of coinductive weak invertibility, with similar properties to its analogue in strict $\omega$-categories. We construct a model structure whose fibrant objects are…

Algebraic Topology · Mathematics 2024-11-01 Clémence Chanavat , Amar Hadzihasanovic

We consider the posets of equivalence relations on finite sets under the standard embedding ordering and under the consecutive embedding ordering. In the latter case, the relations are also assumed to have an underlying linear order, which…

Combinatorics · Mathematics 2024-02-12 V. Ironmonger , N. Ruskuc

Given a symmetric monoidal category $C$ with product $\sqcup$, where the neutral element for the product is an initial object, we consider the poset of $\sqcup$-complemented subobjects of a given object $X$. When this poset has finite…

Combinatorics · Mathematics 2025-07-30 Kevin Ivan Piterman , Volkmar Welker

The category of Hilbert modules may be interpreted as a naive quantum field theory over a base space. Open subsets of the base space are recovered as idempotent subunits, which form a meet-semilattice in any firm braided monoidal category.…

Category Theory · Mathematics 2018-03-05 Pau Enrique Moliner , Chris Heunen , Sean Tull

We work with the structure consisting of all computably enumerable (c.e.) sets ordered by set inclusion. The question we will partially address is which c.e.\ sets are autormorphic to low (or low$_2$ sets. Using work of Miller, we can see…

Logic · Mathematics 2015-12-29 Peter Cholak , Rachel Epstein

We prove a class of equivalences of additive functor categories that are relevant to enumerative combinatorics, representation theory, and homotopy theory. Let $\mathscr{X}$ denote an additive category with finite direct sums and split…

Category Theory · Mathematics 2019-04-01 Stephen Lack , Ross Street

Consider a diagram of quasi-categories that admit and functors that preserve limits or colimits of a fixed shape. We show that any weighted limit whose weight is a projective cofibrant simplicial functor is again a quasi-category admitting…

Category Theory · Mathematics 2015-03-03 Emily Riehl , Dominic Verity

Two semisimple algebraic groups of the same type are said to be motivic equivalent if the motives of the associated projective homogeneous varieties of the same type are isomorphic. We give general criteria of motivic equivalence in terms…

Algebraic Geometry · Mathematics 2013-04-02 Charles De Clercq

We investigate classifications of quasitrivial semigroups defined by certain equivalence relations. The subclass of quasitrivial semigroups that preserve a given total ordering is also investigated. In the special case of finite semigroups,…

Rings and Algebras · Mathematics 2020-05-21 Jimmy Devillet , Jean-Luc Marichal , Bruno Teheux

We study a new notion of reduction between structures called enumerable functors related to the recently investigated notion of computable functors. Our main result shows that enumerable functors and effective interpretability with the…

Logic · Mathematics 2017-08-11 Dino Rossegger

We prove that in the varieties where every compact congruence is a factor congruence and every nontrivial algebra contains a minimal subalgebra, a finitely presented algebra is projective if and only if it has every minimal algebra as its…

Logic · Mathematics 2017-08-11 Alex Citkin

The main goal of this paper is to develop a concept of approximate differentiability of higher order for subsets of the Euclidean space that allows to characterize higher order rectifiable sets, extending somehow well known facts for…

Classical Analysis and ODEs · Mathematics 2020-07-20 Mario Santilli

The consistent systems of idempotents of Meyer and Solleveld allow to construct Serre subcategories of $Rep_R(G)$, the category of smooth representations of a $p$-adic group $G$ with coefficients in $R$. In particular, they were used to…

Representation Theory · Mathematics 2021-02-12 Thomas Lanard

We present novel equivalences in random matrix and tensor models between complex and self-adjoint theories with nontrivial quadratic terms in the action, established through an intermediate field representation. More precisely, we show that…

Mathematical Physics · Physics 2026-03-31 Juan Abranches , Alicia Castro , Reiko Toriumi

Let $R$ be a commutative ring with unit. We consider the homotopy theory of the category of spectral sequences of $R$-modules with the class of weak equivalences given by those morphisms inducing a quasi-isomorphism at a certain fixed page.…

Algebraic Topology · Mathematics 2023-02-22 Muriel Livernet , Sarah Whitehouse

For any block of a finite group over an algebraically closed field of characteristic $2$ which has dihedral, semidihedral, or generalized quaternion defect groups, we determine explicitly the decomposition of the associated diagonal…

Representation Theory · Mathematics 2025-09-19 Robert Boltje , Serge Bouc , Deniz Yılmaz

The complexity of equivalence relations has received much attention in the recent literature. The main tool for such endeavour is the following reducibility: given equivalence relations $R$ and $S$ on natural numbers, $R$ is computably…

Logic · Mathematics 2023-11-09 Nikolay Bazhenov , Keng Meng Ng , Luca San Mauro , Andrea Sorbi

We show that any countable model of a model complete theory has an elementary extension with a "pseudofinite-like" quasidimension that detects dividing.

Logic · Mathematics 2014-10-15 Isaac Goldbring , Henry Towsner

Abelian groups having partial orderings compatible with their binary operations have long been studied in the literature. In particular, lattice-ordered abelian groups constitute a universal-algebraic variety, and thus form a category which…

Rings and Algebras · Mathematics 2012-01-25 Elijah Stines

We give a new construction of the model structure on the category of simplicial sets for homotopy $n$-types, originally due to Elvira-Donazar and Hernandez-Paricio, using a right transfer along the coskeleton functor. We observe that an…

Category Theory · Mathematics 2025-12-23 Chris Kapulkin , Udit Mavinkurve