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We show the vanishing of higher extension groups and torsion groups between linearisation of additive functors from a semi-additive category satisfying some conditions to a category of vector spaces. In particular, we apply our results to…

Category Theory · Mathematics 2026-01-12 Benachir El Allaoui

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

Derived equivalences between finite dimensional algebras do, in general, not pass to centraliser (or other) subalgebras, nor do they preserve homological invariants of the algebras, such as global or dominant dimension. We show that,…

Representation Theory · Mathematics 2016-07-14 Ming Fang , Wei Hu , Steffen Koenig

We present a new aspect of the study of higher derived limits. More precisely, we introduce a complexity measure for the elements of higher derived limits over the directed set $\Omega$ of functions from $\mathbb{N}$ to $\mathbb{N}$ and…

Recent advances in our understanding of higher derived limits carry multiple implications in the fields of condensed and pyknotic mathematics, as well as for the study of strong homology. These implications are thematically diverse,…

Algebraic Topology · Mathematics 2025-08-12 Jeffrey Bergfalk , Chris Lambie-Hanson

We consider several types of non-existence theorems for functors. For example, there are no nontrivial functors from the category of groups (or the category of pointed sets, or vector spaces) to any small category. Another type of questions…

Category Theory · Mathematics 2025-05-20 Emmanuel Dror Farjoun , Sergei O. Ivanov , Aleksandr Krasilnikov , Anatolii Zaikovskii

We shall prove a new non-vanishing theorem for the stable cohomotopy Seiberg-Witten invariant of connected sums of 4-manifolds with positive first Betti number. The non-vanishing theorem enables us to find many new examples of 4-manifolds…

Differential Geometry · Mathematics 2008-04-23 Masashi Ishida , Hirofumi Sasahira

In this paper, we consider inverse limits of $[0,1]$ using upper semicontinuous set-valued functions. We aim to expand on a previous paper exploring the relationship between the existence periodic points of a continuous function to the…

General Topology · Mathematics 2022-09-13 Tavish Dunn , David Ryden

We show that, for every finitely generated group with decidable word problem and undecidable domino problem, there exists a sequence of effective subshifts whose inverse limit is not the topological factor of any effective dynamical system.…

Dynamical Systems · Mathematics 2025-12-19 Sebastián Barbieri , Leo Poirier

Fix $\alpha \in (0,1/3)$. We show that, from a topological point of view, almost all sets $A\subseteq \mathbb{N}$ have the property that, if $A^\prime=A$ for all but $o(n^{\alpha})$ elements, then $A^\prime$ is not a nontrivial sumset…

Number Theory · Mathematics 2022-12-29 Paolo Leonetti

Category theory is the language of homological algebra, allowing us to state broadly applicable theorems and results without needing to specify the details for every instance of analogous objects. However, authors often stray from the realm…

General Mathematics · Mathematics 2025-02-04 Skyler Marks

Attractor-repeller decompositions of isolated invariant sets give rise to so-called connecting homomorphisms. These homomorphisms reveal information on the existence and structure of connecting trajectories of the underlying dynamical…

Dynamical Systems · Mathematics 2018-01-11 Axel Jänig

We investigate the homology of an unbounded noisy sample on $\mathbb{R}^d$, under various assumptions on the sampling density. This investigation is based on previous results by Adler, Bobrowski, and Weinberger (\cite{crackle}), and Owada…

Probability · Mathematics 2019-12-24 Henry-Louis de Kergorlay

Let V be a variety of not necessarily associative algebras, and A an inverse limit of nilpotent algebras A_i\in V, such that some finitely generated subalgebra S \subseteq A is dense in A under the inverse limit of the discrete topologies…

Rings and Algebras · Mathematics 2021-10-15 George M. Bergman

We prove that if $f:I\subset \Bbb R\to \Bbb R$ is of bounded variation, then the noncentered maximal function $Mf$ is absolutely continuous, and its derivative satisfies the sharp inequality $\|DMf\|_1\le |Df|(I)$. This allows us obtain,…

Classical Analysis and ODEs · Mathematics 2010-09-24 J. M. Aldaz , J. Pérez Lázaro

Given an associative graded algebra equipped with a degree +1 differential we define an A-infinity structure that measures the failure of the differential to be a derivation. This can be seen as a non-commutative analog of generalized…

Quantum Algebra · Mathematics 2013-04-24 Kaj Börjeson

We consider pinching cocycles taking values in the space of homeomorphisms of the circle over an hyperbolic base. Using the Invariance Principle of Malicet, we prove that the cocycles having non-zero exponents of contraction are dense. In…

Dynamical Systems · Mathematics 2022-12-27 Catalina Freijo , Karina Marin

Kontsevich and Soibelman has proved a relation between a non-degenerate cyclic homology element of an A-infinity algebra A and its cyclic inner products on the minimal model of A. We find an explicit formula of this correspondence, in terms…

Symplectic Geometry · Mathematics 2014-03-19 Cheol-Hyun Cho , Sangwook Lee

In this note, we discuss the derived functors of infinite products and homotopy limits. $QC(X)$, the category of quasi-coherent sheaves on a Deligne-Mumford stack $X$, usually has the property that the derived functors of product vanish…

Category Theory · Mathematics 2009-02-25 Amit Hogadi , Chenyang Xu

In this paper we introduce a new homology theory devoted to the study of families such as semi-algebraic or subanalytic families and in general to any family definable in an o-minimal structure (such as Denjoy-Carleman definable or $ln-exp$…

Algebraic Geometry · Mathematics 2008-01-15 Guillaume Valette