English
Related papers

Related papers: Covariant functors commuting with direct limits

200 papers

We obtain Morita invariant versions of Eilenberg-Watts type theorems, relating Deligne products of finite linear categories to categories of left exact as well as of right exact functors. This makes it possible to switch between different…

Representation Theory · Mathematics 2019-11-15 Jürgen Fuchs , Gregor Schaumann , Christoph Schweigert

We consider a field $f \circ T_1^{i_1} \circ \cdots \circ T_d^{i_d}$ where $T_1, \dots , T_d$ arecommuting transformations, one of them at least being ergodic. Considering the case of commuting filtrations, we are interested by giving…

Probability · Mathematics 2025-03-27 Christophe Cuny , Jérôme Dedecker , Florence Merlevède

Let $H$ be a Hopf algebra over a field $k$, and $A$ an $H$-comodule algebra. The categories of comodules and relative Hopf modules are then Grothendieck categories with enough injectives. We study the derived functors of the associated Hom…

Rings and Algebras · Mathematics 2007-05-23 S. Caenepeel , T. Guédénon

We prove that the commutator is stable in permutations endowed with the Hamming distance, that is, two permutations that almost commute are near two commuting permutations. Our result extends to $k$-tuples of almost commuting permutations,…

Group Theory · Mathematics 2016-08-08 Goulnara Arzhantseva , Liviu Paunescu

We study relative integral functors for singular schemes and characterise those which preserve boundness and those which have integral right adjoints. We prove that a relative integral functor is an equivalence if and only if its…

Algebraic Geometry · Mathematics 2007-09-24 D. Hernández Ruipérez , A. C. López Martín , F. Sancho de Salas

For a triangulated category with products we develop a method for constructing a nice set of cogenerators, allowing us to prove a formal criterion in order to satisfy Brown representability for covariant functors. We apply this criterion…

Category Theory · Mathematics 2014-10-21 George Ciprian Modoi

We provide necessary and/or sufficient conditions for the stable Hom functors to be finitely presented. When the covariant Hom functor modulo projectives is finitely presented, its defect is isomorphic to the Bass torsion of the fixed…

Category Theory · Mathematics 2024-03-21 Alex Martsinkovsky

We study modular subspaces corresponding to two deformation functors associated to an isolated singularity X_0: the functor Def_{X_0} of deformations of X_0 and the functor Def^s_{X_0} of deformations with section of X_0. After recalling…

Complex Variables · Mathematics 2007-05-23 Tobias Hirsch , Bernd Martin

Let $G$ be a compact and connected Lie group. The Hamiltonian $G$-model functor maps the category of symplectic representations of closed subgroups of $G$ to the category of exact Hamiltonian $G$-actions. Based on previous joint work with…

Symplectic Geometry · Mathematics 2023-08-01 Fabian Ziltener

Given a complete, cocomplete category $\mathcal C$, we investigate the problem of describing those small categories $I$ such that the diagonal functor $\Delta:\mathcal C\to {\rm Functors}(I,\mathcal C)$ is a Frobenius functor. This…

Category Theory · Mathematics 2009-06-04 Alexandru Chirvasitu

We introduce heavily separable functors of the second kind and study them in three different situations. The first of these is with restrictions and extensions of scalars for modules over small preadditive categories. The second is with…

Rings and Algebras · Mathematics 2023-06-30 Abhishek Banerjee , Subhajit Das

We introduce spaces of exponential constructible functions in the motivic setting for which we construct direct image functors in the absolute and relative cases. This allows us to define a motivic Fourier transformation for which we get…

Algebraic Geometry · Mathematics 2011-01-28 R. Cluckers , F. Loeser

We prove a moving lemma for higher Chow groups with modulus, in the sense of Binda-Kerz-Saito, of projective schemes when the modulus is given by a very ample divisor. This provides one of the first cases of moving lemmas for cycles with…

Algebraic Geometry · Mathematics 2016-10-05 Amalendu Krishna , Jinhyun Park

We prove that applying a projective functor to a holonomic simple module over a semi-simple finite dimensional complex Lie algebra produces a module that has an essential semi-simple submodule of finite length. This implies that holonomic…

Representation Theory · Mathematics 2024-01-29 Marco Mackaay , Volodymyr Mazorchuk , Vanessa Miemietz

In this short note we show that under very mild conditions on a functor between exact categories $F:\mathcal{D}\rightarrow\mathcal{E}$ it is possible to derive $F$ at the level of unbounded complexes. We also give applications to deriving…

Category Theory · Mathematics 2021-04-02 Jack Kelly

We establish the exact overlaps conjecture for iterated functions systems on the real line with algebraic contractions and arbitrary translations.

Dynamical Systems · Mathematics 2020-01-15 Ariel Rapaport

We study the problem of characterizing polynomial vector fields that commute with a given polynomial vector field on a plane. It is a classical result that one can write down solution formulas for an ODE that corresponds to a planar vector…

Dynamical Systems · Mathematics 2020-11-17 Joel Nagloo , Alexey Ovchinnikov , Peter Thompson

Codifferentials and coexhausters are used to describe nonhomogeneous approximations of a nonsmooth function. Despite the fact that coexhausters are modern generalizations of codifferentials, the theories of these two concepts continue to…

Optimization and Control · Mathematics 2021-11-29 Majid E. Abbasov

We introduce certain functors from the category of commutative rings (and related categories) to that of $\mathbb{Z}$-algebras (not necessarily associative or commutative). One of the motivating examples is the Leavitt path algebra functor…

We introduce and discuss the notion of naturally full functor. The definition is similar to the definition of separable functor: a naturally full functor is a functorial version of a full functor, while a separable functor is a functorial…

Rings and Algebras · Mathematics 2007-05-23 A. Ardizzoni , S. Caenepeel , C. Menini , G. Militaru