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Associated to a newform $f(z)$ is a Dirichlet series $L_f(s)$ with functional equation and Euler product. Hecke showed that if the Dirichlet series $F(s)$ has a functional equation of a particular form, then $F(s)=L_f(s)$ for some…

Number Theory · Mathematics 2007-05-23 David W. Farmer , Kevin Wilson

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…

A crossed product functor is said to be injective if it takes injective morphisms to injective morphisms. In this paper we show that every locally compact group $G$ admits a maximal injective crossed product $A\mapsto A\rtimes_{\inj}G$.…

Operator Algebras · Mathematics 2020-10-07 Alcides Buss , Siegfried Echterhoff , Rufus Willett

We introduce a notion of extraction-contraction coproduct on twisted bialgebras, that is to say bialgebras in the category of linear species. If $P$ is a twisted bialgebra, a contraction-extraction coproduct sends $P[X]$ to…

Combinatorics · Mathematics 2023-01-24 Loïc Foissy

In this paper we consider commutants in crossed product algebras, for algebras of piece-wise constant functions on the real line acted on by the group of integers $\mathbb{Z}$. The algebra of piece-wise constant functions does not separate…

Rings and Algebras · Mathematics 2019-10-30 Alex Behakanira Tumwesigye , Johan Richter , Sergei Silvestrov

We give a new construction of the equivariant $K$-theory of group actions (cf. Barwick et al.), producing an infinite loop $G$-space for each Waldhausen category with $G$-action, for a finite group $G$. On the category $R(X)$ of retractive…

Algebraic Topology · Mathematics 2019-03-19 Cary Malkiewich , Mona Merling

We construct a covariant functor from a category of Abelian principal bundles over globally hyperbolic spacetimes to a category of *-algebras that describes quantized principal connections. We work within an appropriate differential…

Mathematical Physics · Physics 2014-09-19 Marco Benini , Claudio Dappiaggi , Alexander Schenkel

It is well-known that the maximalization of a coaction of a locally compact group on a C*-algebra enjoys a universal property. We show how this important property can be deduced from a categorical framework by exploiting certain properties…

Operator Algebras · Mathematics 2023-08-17 Erik Bédos , S. Kaliszewski , John Quigg , Jonathan Turk

Given a locally compact group $G$, we study the smallest exact crossed-product functor $(A,G,\alpha)\mapsto A\rtimes_{\mathcal E} G$ on the category of $G$-$C^*$-dynamical systems. As an outcome, we show that the smallest exact…

Operator Algebras · Mathematics 2020-02-21 Alcides Buss , Siegfried Echterhoff , Rufus Willett

This paper presents a systematic study of coproducts. This is carried out principally, but not exclusively, for finitely generated quasivarieties A that admit a (term) reduct in the variety D of bounded distributive lattices. In this…

Rings and Algebras · Mathematics 2013-08-22 L. M. Cabrer , H. A. Priestley

We study selfadjoint functors acting on categories of finite dimensional modules over finite dimensional algebras with an emphasis on functors satisfying some polynomial relations. Selfadjoint functors satisfying several easy relations, in…

Representation Theory · Mathematics 2011-09-08 Troels Agerholm , Volodymyr Mazorchuk

The purpose of this this paper is to generalize the functors arising from the theory of Witt vectors duto to Cartier. Given a polynomial $g(q)\in \mathbb Z[q]$, we construct a functor ${\overline {W}}^{g(q)}$ from the category of $\mathbb…

Rings and Algebras · Mathematics 2015-03-26 Young-Tak Oh

Let $G$ and $A$ be objects of a finitely cocomplete homological category $\mathbb C$. We define a notion of an (internal) action of $G$ of $A$ which is functorially equivalent with a point in $\mathbb C$ over $G$, i.e. a split extension in…

Category Theory · Mathematics 2010-03-02 Manfred Hartl , Bruno Loiseau

In this paper, we first introduce stable functors with respect to a preenveloping/precovering subcategory and investigate some of their properties. Using that we then introduce and study a relative complete cohomology theory in abelian…

Rings and Algebras · Mathematics 2023-10-06 Shoutao Guo , Li Liang

Let $\Cc$ and $\Dd$ be two corings over a ring $A$ and $\Cc\stackrel{\lambda}{\longrightarrow}\Dd$ be a morphism of corings. We investigate the situation when the associated induced ("corestriction of scalars") functor…

Quantum Algebra · Mathematics 2007-05-23 Miodrag C. Iovanov

For discrete Hecke pairs $(G,H)$, we introduce a notion of covariant representation which reduces in the case where $H$ is normal to the usual definition of covariance for the action of $G/H$ on $c_0(G/H)$ by right translation; in many…

Operator Algebras · Mathematics 2007-05-23 Astrid an Huef , S. Kaliszewski , Iain Raeburn

We introduce Hom-actions, semi-direct product and establish the equivalence between split extensions and the semi-direct product extension of Hom-Leibniz algebras. We analyze the functorial properties of the universal ({\alpha})-central…

Rings and Algebras · Mathematics 2013-09-23 J. M. Casas , N Pacheco Regon

We adopt the viewpoint that topological And\'e-Quillen theory for commutative $S$-algebras should provide usable (co)homology theories for doing calculations in the sense traditional within Algebraic Topology. Our main emphasis is on…

Algebraic Topology · Mathematics 2017-03-30 Andrew Baker

We define a functor which gives the "global rank of a quiver representation" and prove that it has nice properties which make it a generalization of the rank of a linear map. We demonstrate how to construct other "rank functors" for a…

Representation Theory · Mathematics 2009-03-10 Ryan Kinser

We introduce a functor $\mathfrak{M}:\mathbf{Alg}\times\mathbf{Alg}^\mathrm{op}\rightarrow\mathrm{pro}\text{-}\mathbf{Alg}$ constructed from representations of $\mathrm{Hom}_\mathbf{Alg}(A,B\otimes ? )$. As applications, the following items…

K-Theory and Homology · Mathematics 2022-05-06 Maysam Maysami Sadr