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The notion of defect of a finitely presented functor on a module category is extended to arbitrary additive functors. The new defect and the contravariant Yoneda embedding form a right adjoint pair. The main result identifies the defect of…

Representation Theory · Mathematics 2024-03-21 Alex Martsinkovsky

We study the category $\mathcal{O}$ for a general Coxeter system using a formulation of Fiebig. The translation functors, the Zuckerman functors and the twisting functors are defined. We prove the fundamental properties of these functors,…

Representation Theory · Mathematics 2009-04-20 Noriyuki Abe

We consider a fixed free and proper action of a locally compact group $G$ on a space $T$, and actions $\alpha:G\to \Aut A$ on $C^*$-algebras for which there is an equivariant embedding of $(C_0(T),\rt)$ in $(M(A),\alpha)$. A recent theorem…

Operator Algebras · Mathematics 2009-07-06 Astrid an Huef , S. Kaliszewski , Iain Raeburn , Dana P. Williams

The aim of this paper is to prove characterization theorems for field homomorphisms. More precisely, the main result investigates the following problem. Let $n\in \mathbb{N}$ be arbitrary, $\mathbb{K}$ a field and $f_{1}, \ldots,…

Commutative Algebra · Mathematics 2018-10-30 Eszter Gselmann , Gergely Kiss , Csaba Vincze

We study polynomial comonads and polynomial bicomodules. Polynomial comonads amount to categories. Polynomial bicomodules between categories amount to parametric right adjoint functors between corresponding copresheaf categories. These may…

Category Theory · Mathematics 2026-05-25 David I. Spivak , Richard Garner , Aaron David Fairbanks

Bruinier and Ono recently developed the theory of generalized Borcherds products, which uses coefficients of certain Maass forms as exponents in infinite product expansions of meromorphic modular forms. Using this, one can use classical…

Number Theory · Mathematics 2014-12-30 Jen Berg , Abel Castillo , Robert Grizzard , Vítězslav Kala , Richard Moy , Chongli Wang

Let $h$ be a connective homology theory. We construct a functorial relative plus construction as a Bousfield localization functor in the category of maps of spaces. It allows us to associate to a pair $(X, H)$ consisting of a connected…

Algebraic Topology · Mathematics 2023-03-21 Guille Carrion Santiago , Jerome Scherer

As part of the study of correspondence functors, the present paper investigates their tensor product and proves some of its main properties. In particular, the correspondence functor associated to a finite lattice has the structure of a…

Representation Theory · Mathematics 2019-03-06 Serge Bouc , Jacques Thévenaz

We investigate criteria for algebra extensions that are of Galois type with respect to the coaction of a Hopf algebra or, more generally, a one-sided quotient of a Hopf algebra, or with respect to an entwining. We study the module- and…

Quantum Algebra · Mathematics 2007-05-23 P. Schauenburg , H. -J. Schneider

We define the partial group cohomology as the right derived functor of the functor of partial invariants, we relate this cohomology with partial derivations and with the partial augmentation ideal and we show that there exists a…

Rings and Algebras · Mathematics 2017-06-23 Edson Ribeiro Alvares , Marcelo Muniz Alves , Maria Julia Redondo

We develop a theory of parametrized geometric cobordism by introducing smooth Thom stacks. This requires identifying and constructing a smooth representative of the Thom functor acting on vector bundles equipped with extra geometric data,…

Algebraic Topology · Mathematics 2017-09-05 Daniel Grady , Hisham Sati

We develop a generalization of quantitative $K$-theory, which we call controlled $K$-theory. It is powerful enough to study the $K$-theory of crossed product of $C^*$-algebras by action of \'etale groupoids and discrete quantum groups. In…

K-Theory and Homology · Mathematics 2017-10-18 Clément Dell'Aiera

Recently, Shehata et al. [37] introduced the $_{r+1}R_{s,k}(B,C,z)$ matrix function and established some properties. The aim of this study established to devote and derive certain basic properties including analytic properties, recurrence…

General Mathematics · Mathematics 2024-03-18 Ayman Shehata

Difference balanced functions from $F_{q^n}^*$ to $F_q$ are closely related to combinatorial designs and naturally define $p$-ary sequences with the ideal two-level autocorrelation. In the literature, all existing such functions are…

Combinatorics · Mathematics 2013-10-01 Alexander Pott , Qi Wang

We consider isomorphisms between quotient algebras of $\prod_{n=0}^{\infty} \mathbb{M}_{k(n)}(\mathbb{C})$ associated with Borel ideals on $\mathbb{N}$ and prove that it is relatively consistent with \textbf{ZFC} that all of these…

Operator Algebras · Mathematics 2014-06-23 Saeed Ghasemi

We construct explicit models of universal $H \mathbb{Z}[J^{-1}]$-acyclic spaces $\mathcal M$, for any subset $J$ of the prime numbers. The corresponding nullification functors provide thus plus construction functors for ordinary homology…

Algebraic Topology · Mathematics 2025-12-10 Guille Carrión Santiago , Ramón Flores , Jérôme Scherer

We prove that if E and F are large ideals of B(G) for which the associated coaction functors are exact, then the same is true for the intersection of E and F. We also give an example of a coaction functor whose restriction to the maximal…

Operator Algebras · Mathematics 2016-03-31 S. Kaliszewski , Magnus B. Landstad , John Quigg

Given a partial action \alpha of a group G on an associative algebra A we consider the crossed product A x_\alpha G. Using the algebras of multipliers of ideals of A we prove that A x_\alpha G is associative, provided that all ideals of A…

Rings and Algebras · Mathematics 2010-03-16 M. Dokuchaev , R. Exel

It is known that homology and inverse limit functors do not commute. In the paper we consider this very problem and find its application for various homology theories. In particular, on the category of general topological spaces, there are…

Algebraic Topology · Mathematics 2024-03-20 Anzor Beridze , Leonard Mdzinarishvili

Protoadditive functors are designed to replace additive functors in a non-abelian setting. Their properties are studied, in particular in relationship with torsion theories, Galois theory, homology and factorisation systems. It is shown how…

Category Theory · Mathematics 2015-04-20 Tomas Everaert , Marino Gran