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For any dg algebra $A$ we construct a closed model category structure on dg $A$-modules such that the corresponding homotopy category is compactly generated by dg $A$-modules that are finitely generated and free over $A$ (disregarding the…

Category Theory · Mathematics 2022-05-12 Ai Guan , Andrey Lazarev

In this paper we study the question of how to transfer homotopic structure from the category sD of simplicial objects in a fixed category D to D. To this end we use a sort of homotopy colimit s : sD --> D, which we call simple functor. For…

Algebraic Geometry · Mathematics 2011-10-12 Beatriz Rodriguez Gonzalez

The purpose of this paper is to develop a homotopical algebra for graphs, relevant to zeta series and spectra of finite graphs. More precisely, we define a Quillen model structure in a category of graphs (directed and possibly infinite,…

Combinatorics · Mathematics 2008-02-27 Terrence Bisson , Aristide Tsemo

We recall the notions of a graded cocategory, conilpotent cocategory, morphisms of such (cofunctors), coderivations and define their analogs in $\mathbb L$-filtered setting. The difference with the existing approaches: we do not impose any…

Category Theory · Mathematics 2020-10-13 Volodymyr Lyubashenko

We give an especially simple proof of a theorem in graph theory that forms the key part of the solution to a problem in commutative algebra, on how to characterize the integral closure of a polynomial ring generated by quadratic monomials.

Commutative Algebra · Mathematics 2011-06-09 Peter M. Johnson

We generalize the finiteness theorem for the locus of Hodge classes with fixed self-intersection number, due to Cattani, Deligne, and Kaplan, from Hodge classes to self-dual classes. The proof uses the definability of period mappings in the…

Algebraic Geometry · Mathematics 2026-05-06 Benjamin Bakker , Thomas W. Grimm , Christian Schnell , Jacob Tsimerman

In this paper we prove that for any model category, the Bousfield-Kan construction of the homotopy colimit is the absolute left derived functor of the colimit. This is achieved by showing that the Bousfield-Kan homotopy colimit is moreover…

Algebraic Geometry · Mathematics 2012-02-17 Beatriz Rodriguez Gonzalez

We introduce pseudoalgebras for relative pseudomonads and develop their theory. For each relative pseudomonad $T$, we construct a free--forgetful relative pseudoadjunction that exhibits the bicategory of $T$-pseudoalgebras as terminal among…

Category Theory · Mathematics 2025-01-23 Nathanael Arkor , Philip Saville , Andrew Slattery

A simple criterion for a functor to be finitary is presented: we call $F$ finitely bounded if for all objects $X$ every finitely generated subobject of $FX$ factorizes through the $F$-image of a finitely generated subobject of $X$. This is…

Category Theory · Mathematics 2019-10-22 Jiří Adámek , Stefan Milius , Lurdes Sousa , Thorsten Wißmann

Given a bounding class $B$, we construct a bounded refinement $BK(-)$ of Quillen's $K$-theory functor from rings to spaces. $BK(-)$ is a functor from weighted rings to spaces, and is equipped with a comparison map $BK \to K$ induced by…

K-Theory and Homology · Mathematics 2012-04-19 J. Fowler , C. Ogle

It is well known that Barr and Beck's definition of comonadic homology makes sense also with a functor of coefficients taking values in a semi-abelian category instead of an abelian one. The question arises whether such a homology theory…

Algebraic Topology · Mathematics 2009-04-16 Julia Goedecke , Tim Van der Linden

In this paper we prove a characterization of quotients of Abelian varieties by the actions of finite groups that are free in codimension-one via some vanishing conditions on the orbifold Chern classes. The characterization is given among a…

Algebraic Geometry · Mathematics 2016-10-18 Steven Lu , Behrouz Taji

We develop further the theory of weak factorization systems and algebraic weak factorization systems. In particular, we give a method for constructing (algebraic) weak factorization systems whose right maps can be thought of as (uniform)…

Category Theory · Mathematics 2017-09-29 Nicola Gambino , Christian Sattler

In his fundamental work, Quillen developed the theory of the cotangent complex as a universal abelian derived invariant, and used it to define and study a canonical form of cohomology, encompassing many known cohomology theories. Additional…

Algebraic Topology · Mathematics 2023-11-21 Yonatan Harpaz , Joost Nuiten , Matan Prasma

In the first half of this article we define a new weight homology functor on Voevodsky's category of effective motives, and investigate some of its properties. In special cases we recover Gillet-Soul\'e's weight homology, and Geisser's…

Algebraic Geometry · Mathematics 2014-11-24 Shane Kelly , Shuji Saito

We give sufficient conditions for the existence of a Quillen model structure on small categories enriched in a given monoidal model category. This yields a unified treatment for the known model structures on simplicial, topological, dg- and…

Algebraic Topology · Mathematics 2016-04-04 Clemens Berger , Ieke Moerdijk

We prove that for every prime $p$ algebraically clean graphs of groups are virtually residually $p$-finite and cohomologically $p$-complete. We also prove that they are cohomologically good. We apply this to certain $2$-dimensional Artin…

Group Theory · Mathematics 2023-12-27 Kasia Jankiewicz , Kevin Schreve

We contribute XTT, a cubical reconstruction of Observational Type Theory which extends Martin-L\"of's intensional type theory with a dependent equality type that enjoys function extensionality and a judgmental version of the unicity of…

Logic in Computer Science · Computer Science 2021-04-20 Jonathan Sterling , Carlo Angiuli , Daniel Gratzer

The cofinality quantifiers were introduced by Shelah as an example of a compact logic stronger than first-order logic. We show that the classes of models axiomatized by these quantifiers can be turned into an Abstract Elementary Class by…

Logic · Mathematics 2025-04-16 Will Boney

Let $\mathscr{A}$ be a connected cochain DG algebra and $P$ a DG $\mathscr{A}$-module such that its underlying graded module $P^{\#}$ is a finitely generated $\mathscr{A}^{\#}$-module. We show that $P$ is semi-free if it is semi-projective…

Rings and Algebras · Mathematics 2025-09-19 Xuefeng Mao , Biyan Zhu