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Related papers: Mackey 2-functors and Mackey 2-motives

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We examine the projective dimensions of Mackey functors and cohomological Mackey functors. We show over a field of characteristic $p$ that cohomological Mackey functors are Gorenstein if and only if Sylow $p$-subgroups are cyclic or…

Representation Theory · Mathematics 2015-03-16 S. Bouc , R. Stancu , P. J. Webb

For a finite group $G$, the so-called $G$-Mackey functors form an abelian category $M(G)$ that has many applications in the study of $G$-equivariant stable homotopy. One would expect that the derived category $D(M(G))$ would be similarly…

K-Theory and Homology · Mathematics 2010-03-17 D. Kaledin

Inspired by equivariant homotopy theory, equivariant algebra studies generalisations of G-Mackey functors that do not have all transfer maps (also known as induction maps), for G a finite group. These incomplete Mackey functors have…

Algebraic Topology · Mathematics 2025-11-05 David Barnes , Michael A. Hill , Magdalena Kedziorek

Let $G$ be a finite group and $R$ be a commutative ring. The Mackey algebra $\mu_{R}(G)$ shares a lot of properties with the group algebra $RG$ however, there are some differences. For example, the group algebra is a symmetric algebra and…

Group Theory · Mathematics 2014-06-18 Baptiste Rognerud

The Mackey-type identity mentioned in the title relates the operations of parabolic induction and restriction for invariant functions on the Lie algebras of the finite unitary groups $U(N, q^2)$. This result is applied to constructing…

Representation Theory · Mathematics 2024-08-15 Cesar Cuenca , Grigori Olshanski

We develop the fundamentals of Mackey functors in the setup of fusion systems including an acyclicity condition as well as a parametrization and an explicit description of simple Mackey functors. Using this machinery we extend Dwyer's…

Algebraic Topology · Mathematics 2014-12-02 Antonio Díaz , Sejong Park

Throughout this paper $G$ is a fixed group, and $k$ is a fixed field. All categories are assumed to be $k$-linear. First we give a systematic way to induce $G$-precoverings by adjoint functors using a 2-categorical machinery, which unifies…

Representation Theory · Mathematics 2024-02-08 Rasool Hafezi , Hideto Asashiba , Mohammad Hossein Keshavarz

This is an extended version of my earlier articel "Projective and injective objects in symmetric categorical groups. arXiv:1007.0121v1." Several new facts added, including the material on the derived 2-functors and the proof of the…

Category Theory · Mathematics 2010-12-24 Teimuraz Pirashvili

We introduce group-theoretical fusion 2-categories, a strong categorification of the notion of a group-theoretical fusion 1-category. Physically speaking, such fusion 2-categories arise by gauging subgroups of a global symmetry. We show…

Category Theory · Mathematics 2025-02-24 Thibault D. Décoppet , Matthew Yu

We extend the theory of distributive series of monads of \cite{EC1} by extending the definition to include an $\bN$-indexed collection of monads. Under certain conditions, distributive series of monads will have a colimit in the category of…

Category Theory · Mathematics 2025-10-28 Johnathon Taylor

Let $R$ be a commutative unital ring. We construct a category $\mathcal{C}_R$ of fractions $X/G$, where $G$ is a finite group and $X$ is a finite $G$-set, and with morphisms given by $R$-linear combinations of spans of bisets. This category…

Category Theory · Mathematics 2019-10-02 Jesús Ibarra , Alberto G. Raggi-Cárdenas , Nadia Romero

We classify the primitive idempotents of the $p$-local complex representation ring of a finite group $G$ in terms of the cyclic subgroups of order prime to $p$ and show that they all come from idempotents of the Burnside ring. Our results…

Algebraic Topology · Mathematics 2020-10-12 Benjamin Böhme

We generalize the construction of tensor categories of endomorphisms of a type III factor $M$ associated with a $G$-kernel, from the case of a discrete group $G$ to that of a compact second countable group. Our approach is based on the…

Operator Algebras · Mathematics 2026-05-19 Marcel Bischoff , Pradyut Karmakar

Categories are coreflectively embedded in multicategories via the "discrete cocone" construction, the right adjoint being given by the monoid construction. Furthermore, the adjunction lifts to the "cartesian level": preadditive categories…

Category Theory · Mathematics 2013-04-11 Claudio Pisani

We set up a fibred categorical theory of obstruction and classification of morphisms that specializes to the one of monoidal functors between categorical groups and also to the Schreier-Mac Lane theory of group extensions. Further…

Category Theory · Mathematics 2021-04-14 Alan S. Cigoli , Sandra Mantovani , Giuseppe Metere , Enrico M. Vitale

The behaviour of limits of weak morphisms in 2-dimensional universal algebra is not 2-categorical in that, to fully express the behaviour that occurs, one needs to be able to quantify over strict morphisms amongst the weaker kinds.…

Category Theory · Mathematics 2022-01-31 John Bourke

Systematically using the language of groupoids, we survey the theory of global Mackey functors, global Green functors and global power functors. Given a global power functor, we study rings with similar operations. The example of n-class…

Representation Theory · Mathematics 2013-01-22 Nora Ganter

We consider the 3-category $2\mathfrak{C}at$ whose objects are 2-categories, 1-morphisms are lax functors, 2-morphisms are lax transformations and 3-morphisms are modifications. The aim is to show that it carries interesting…

Representation Theory · Mathematics 2025-08-11 Fei Xu , Maoyin Zhang

Consider the Mackey functor assigning to each finite group G the Green ring of finitely generated kG-modules, where k is a field of characteristic p>0. Thevenaz foresaw in 1988 that the class of primordial groups for this functor is the…

Representation Theory · Mathematics 2013-02-11 Alberto Raggi-Cardenas , Nadia Romero

We investigate the structure of the monomial Burnside biset functor over a field of characteristic zero, with particular focus on its restriction kernels. For each finite \( p \)-group \( G \), we give an explicit description of the…

Representation Theory · Mathematics 2026-05-22 İbrahim Kaan Aslan , Olcay Coşkun