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We show that for any quantale $\mathcal{Q}$, a $\mathcal{Q}$-category is skeletal and complete if and only if it is injective with respect to fully faithful $\mathcal{Q}$-functors. This is a special case of known theorems due to Hofmann and…

Category Theory · Mathematics 2021-10-08 Soichiro Fujii

Given an idempotent complete additive category, we show the there is an explicitly constructed topological space such that the lattice of exact substructures is anti-isomorphic to the lattice of closed subsets. In the special case that the…

Representation Theory · Mathematics 2026-02-02 Julia Sauter

We present a Langlands dual realization of the putative category of affine character sheaves. Namely, we calculate the categorical center and trace (also known as the Drinfeld center and trace, or categorical Hochschild cohomology and…

Representation Theory · Mathematics 2019-02-20 David Ben-Zvi , David Nadler , Anatoly Preygel

We introduce the notion of an $n$-exact dg-category. This notion provides a higher analogue of Chen's exact dg-category, in the sense that the case where $n$ equals 1 recovers exact dg-categories. We prove that, under a suitable vanishing…

Category Theory · Mathematics 2026-04-08 Nao Mochizuki , Hiroyuki Nakaoka

We give a criterion for cohomological symmetry in a triangulated category. As an application, we show that such cohomological symmetry holds for all pairs of modules over any exterior algebra.

Representation Theory · Mathematics 2011-05-03 Petter Andreas Bergh , Steffen Oppermann

I give an elementary proof of the known fact that the category $\mathfrak{F} \left( \Delta \right)$ of $\Delta -$filtered modules, associated to a given finite homological system $\left( \Delta ; \Omega , \leq \right) ,$ is closed under…

Representation Theory · Mathematics 2021-05-07 Jesús Efrén Pérez Terrazas

We present an intrinsic and concrete development of the subdivision of small categories, give some simple examples and derive its fundamental properties. As an application, we deduce an alternative way to compare the homotopy categories of…

Algebraic Topology · Mathematics 2018-07-10 Matias Luis del Hoyo

We give sufficient conditions which ensure that a functor of finite length from an additive category to finite-dimensional vector spaces has a projective resolution whose terms are finitely generated. For polynomial functors, we study also…

K-Theory and Homology · Mathematics 2023-07-14 Aurélien Djament , Antoine Touzé

We prove a motivic version of Landweber's exact functor theorem from topology. The main result is that the assignment given by a Landweber-type formula using the MGL-homology of a motivic spectrum defines a homology theory on the stable…

Algebraic Geometry · Mathematics 2009-11-02 Niko Naumann , Paul Arne Østvær , Markus Spitzweck

We provide a criterion for the existence of right approximations in cocomplete additive categories; it is a straightforward generalisation of a result due to El Bashir. This criterion is used to construct adjoint functors in homotopy…

Category Theory · Mathematics 2010-06-24 Henning Krause

In a perfect category every object has a minimal projective resolution. We give a criterion for the category of modules over a categorygraded algebra to be perfect.

Category Theory · Mathematics 2016-02-09 Ana Paula Santana , Ivan Yudin

We give a criterion for maps on ultrametric spaces to be surjective and to preserve spherical completeness. We show how Hensel's Lemma and the multi-dimensional Hensel's Lemma follow from our result. We give an easy proof that the latter…

Commutative Algebra · Mathematics 2013-04-02 Franz-Viktor Kuhlmann

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 show that diagrammatic sets, a topologically sound alternative to polygraphs and strict $\omega$-categories, admit an internal notion of equivalence in the sense of coinductive weak invertibility. We prove that equivalences have the…

Category Theory · Mathematics 2025-12-23 Clémence Chanavat , Amar Hadzihasanovic

We define a class of local Shimura varieties that contains some local Shimura varieties for exceptional groups, and for this class, we construct a functor from $\left(G, \mu\right)$-displays to $p$-divisible groups. As an application, we…

Algebraic Geometry · Mathematics 2026-05-20 Mohammad Hadi Hedayatzadeh , Ali Partofard

In this paper we prove an $\infty$-categorical version of the reflection theorem of Ad\'amek-Rosick\'y. Namely, that a full subcategory of a presentable $\infty$-category which is closed under limits and $\kappa$-filtered colimits is a…

Algebraic Topology · Mathematics 2022-07-20 Shaul Ragimov , Tomer M. Schlank

We give a precise, computable formula for comparing $\lambda$-invariants between modular forms in the anticyclotomic indefinite setting where the Selmer groups have positive rank. This is an improvement of Hatley-Lei \cite{HL19, HL21} where…

Number Theory · Mathematics 2025-10-16 Dac-Nhan-Tam Nguyen

We introduce a new division formula on projective space which provides explicit solutions to various polynomial division problems with sharp degree estimates. We consider simple examples as the classical Macaulay theorem as well as a quite…

Complex Variables · Mathematics 2009-08-21 Mats Andersson , Elin Götmark

The perturbation lemma and the homotopy transfer for L-infinity algebras is proved in a elementary way by using a relative version of the ordinary perturbation lemma for chain complexes and the coalgebra perturbation lemma.

K-Theory and Homology · Mathematics 2012-09-14 Marco Manetti

Huayi Chen introduces the notion of an approximable graded algebra, which he uses to prove a Fujita-type theorem in the arithmetic setting, and asked if any such algebra is the graded ring of a big line bundle on a projective variety. This…

Algebraic Geometry · Mathematics 2026-05-27 Catriona Maclean