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We study reducing invariants of modules related to certain homological properties. For modules of finite reducing projective dimension, we establish grade inequalities. We prove that if $\mathbb{P}$ is the (uniform) Auslander condition, or…

Commutative Algebra · Mathematics 2026-04-15 Tokuji Araya , Naoya Hiramatsu , Ryo Takahashi

In this short note, we present a persistence module approach to directed cohomology, dual to the directed homology introduced by the author in a previous article. We lay out the first properties of directed cohomology and in particular of…

Algebraic Topology · Mathematics 2026-03-13 Eric Goubault

We study Mittag-Leffler conditions on modules providing relative versions of classical results by Raynaud and Gruson. We then apply our investigations to several contexts. First of all, we give a new argument for solving the Baer splitting…

Rings and Algebras · Mathematics 2007-05-23 Lidia Angeleri-Hugel , Dolors Herbera

We present applications of contramodule techniques to the Enochs conjecture about covers and direct limits, both in the categorical tilting context and beyond. In the $n$-tilting-cotilting correspondence situation, if $\mathsf A$ is a…

Category Theory · Mathematics 2021-09-15 Silvana Bazzoni , Leonid Positselski

We study the positive-operator-valued measures on the projective real line covariant with respect to the projective group, assuming that the energy is a positive operator. This problem is similar to the more complicated problem of finding…

Quantum Physics · Physics 2007-05-23 N. Pinamonti , M. Toller

The aim of this paper is to prove the existence of inductive and inverse limits of direct and inverse systems in a certain category of compact metric spaces as well as of compact metric groups. Some applications are presented.

General Topology · Mathematics 2022-11-28 Kamil Urbaś

We study a triangulated category $\mathscr S$ that admits a full and strong exceptional sequence of three objects with one-dimensional Hom spaces. We show that the isomorphism classes of exact functors from $\mathscr S$ to another…

Algebraic Geometry · Mathematics 2026-01-30 Alberto Canonaco , Mattia Ornaghi

We introduce an exact functor defined on multigraded modules which we call the expansion functor and study its homological properties. The expansion functor applied to a monomial ideal amounts to substitute the variables by monomial prime…

Commutative Algebra · Mathematics 2012-05-17 Shamila Bayati , Jürgen Herzog

For a variety $\mathcal{V}$, it has been recently shown that binary products commute with arbitrary coequalizers locally, i.e., in every fibre of the fibration of points $\pi: \mathrm{Pt} (\mathbb{C}) \rightarrow \mathbb{C}$, if and only if…

Category Theory · Mathematics 2020-11-03 Michael Hoefnagel

In this paper we will study the homological properties of various natural modules associated to the Fourier algebra of a locally compact group. In particular, we will focus on the question of identifying when such modules will be projective…

Functional Analysis · Mathematics 2014-02-26 Brian E. Forrest , Hun Hee Lee , Ebrahim Samei

We find a near detailed balance solution to the relativistic Boltzmann equation under the relaxation time approximation with a collision term which differs from the Anderson-Witting model and is dependent on the stationary observer. Using…

General Relativity and Quantum Cosmology · Physics 2022-12-08 Song Liu , Xin Hao , Shaofan Liu , Liu Zhao

We give a characterization, in terms of Galois infinite comatrix corings, of the corings that decompose as a direct sum of left comodules which are finitely generated as left modules. Then we show that the associated rational functor is…

Rings and Algebras · Mathematics 2009-02-16 L. El Kaoutit , J. Gómez-Torrecillas

In connection with the Fuglede conjecture, we study the existence of commuting self-adjoint extensions of the partial differential operators on arbitrary, possibly disconnected domains in $\br^d$, the associated unitary group, the spectral…

Functional Analysis · Mathematics 2025-11-24 Piyali Chakraborty , Dorin Ervin Dutkay

We call a tensor functor $F:\mathcal{C}\to\mathcal{D}$ between finite tensor categories $\otimes$-Frobenius if its left and right adjoints are isomorphic as $\mathcal{C}$-bimodule functors. We give several characterizations of this notion…

Quantum Algebra · Mathematics 2026-02-24 David Jaklitsch , Harshit Yadav

Let $G= {\rm Spec} A$ be an affine $R$-monoid scheme. We prove that the category of dual functors (over the category of commutative $R$-algebras) of $G$-modules is equivalent to the category of dual functors of ${\mathcal A}^*$-modules. We…

Algebraic Geometry · Mathematics 2009-08-31 Amelia Alvarez , Carlos Sancho , Pedro Sancho

In this paper we study the constraints imposed by conformal invariance on extended objects a.k.a defects in a conformal field theory. We identify a particularly nice class of defects that is closed under conformal transformations.…

High Energy Physics - Theory · Physics 2016-02-23 Abhijit Gadde

Invariant conditions for conformable fractional problems of the calculus of variations under the presence of external forces in the dynamics are studied. Depending on the type of transformations considered, different necessary conditions of…

Optimization and Control · Mathematics 2017-04-14 Matheus J. Lazo , Delfim F. M. Torres

We develop the basic properties of the higher commutator for congruence modular varieties.

Logic · Mathematics 2017-03-07 Andrew Moorhead

For any additive functor from modules (or, more generally, from an abelian category with enough projectives or injectives), we construct long sequences tying up together the derived functors, the satellites, and the stabilizations of the…

Representation Theory · Mathematics 2025-04-30 Alex Martsinkovsky

We systematically develop the theory of definable functors between compactly generated triangulated categories. Such functors preserve pure triangles, pure injective objects, and definable subcategories, and as such appear in a wide range…

Category Theory · Mathematics 2025-03-03 Isaac Bird , Jordan Williamson