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Related papers: Bi-incomplete Tambara functors

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Given a finite group $G$ acting on a ring $R$, Merling constructed an equivariant algebraic $K$-theory $G$-spectrum, and work of Malkiewich and Merling, as well as work of Barwick, provides an interpretation of this construction as a…

Algebraic Topology · Mathematics 2021-02-16 Thomas Brazelton

Let $G$ be a finite group. A $G$-Tambara functor can be defined as a product-preserving functor $\mathcal{P}_G \to \mathsf{Set}$ (satisfying one additional condition), where $\mathcal{P}_G$ is a category that is constructed in a…

Algebraic Topology · Mathematics 2024-09-23 Ben Spitz

We define the notion of an $\mathcal{RO}(G)$-graded Tambara functor and prove that any $G$-spectrum with norm multiplication gives rise to such an $\mathcal{RO}(G)$-graded Tambara functor.

Algebraic Topology · Mathematics 2023-03-14 Vigleik Angeltveit , Anna Marie Bohmann

The first word in the title is intended in a sense suggested by Lawvere and Schanuel whereby finite sets are objective natural numbers. At the objective level, the axioms defining abstract Mackey and Tambara functors are categorically…

Category Theory · Mathematics 2025-04-22 Ross Street

We compute Mackey functor-valued Tor over certain free incomplete Tambara functors, generalizing the computation of Tor over a polynomial ring on one generator. In contrast with the classical situation where the resulting Tor groups vanish…

Algebraic Topology · Mathematics 2025-07-15 David Mehrle , J. D. Quigley , Michael Stahlhauer

Structures where we have both a contravariant (pullback) and a covariant (pushforward) functoriality that satisfy base change can be encoded by functors out of ($\infty$-)categories of spans (or correspondences). In this paper we study the…

Category Theory · Mathematics 2021-11-30 Elden Elmanto , Rune Haugseng

In this paper, we analyse the global dimension of the category of rational incomplete Mackey functors over a finite abelian group. Incomplete Mackey functors have recently risen to prominence in algebraic topology and hence it is valuable…

Algebraic Topology · Mathematics 2026-05-06 David Barnes , Anna Marie Bohmann , Michael A. Hill , Magdalena Kędziorek

In equivariant algebra, Mackey functors replace abelian groups and incomplete Tambara functors replace commutative rings. In this context, we prove that equivariant Hochschild homology can sometimes be computed using Mackey functor-valued…

Algebraic Topology · Mathematics 2024-07-29 David Mehrle , J. D. Quigley , Michael Stahlhauer

If we are given an $H$-$G$-biset $U$ for finite groups $G$ and $H$, then any Mackey functor on $G$ can be transformed by $U$ into a Mackey functor on $H$. In this article, we show that the biset transformation is also applicable to Tambara…

Category Theory · Mathematics 2013-11-19 Hiroyuki Nakaoka

Tambara functors arise in equivariant homotopy theory as the structure adherent to the homotopy groups of a coherently commutative equivariant ring spectrum. We show that if $k$ is a field-like $C_{p^n}$-Tambara functor, then $k$ is the…

Algebraic Topology · Mathematics 2025-03-07 Noah Wisdom

We construct a faithful and conservative functor from prisms to $C_{p^\infty}$-Tambara functors; in appropriate situations, this gives an algebraic description of $\underline\pi_0{\mathrm{TC}^-}$. We also present two integral variants using…

Number Theory · Mathematics 2023-09-12 Yuri J. F. Sulyma

Let $G$ be a finite group. In [HTW], Hambleton, Taylor and Williams have considered the question of comparing Mackey functors for $G$ and biset functors defined on subgroups of $G$ and bifree bisets as morphisms. This paper proposes a…

Group Theory · Mathematics 2013-03-28 Serge Bouc

Suppose $G$ is a finite group. In this paper, we construct an equivalence between the $\infty$-category of algebras over an $N_{\infty}$-operad $\mathcal{O}$ associated to a $G$-indexing system $\mathcal{I}$ and the corresponding…

Algebraic Topology · Mathematics 2026-04-03 Gregoire Marc

We provide a complete characterization of the equivariant commutative ring structures of all the factors in the idempotent splitting of the G-equivariant sphere spectrum, including their Hill-Hopkins-Ravenel norms, where G is any finite…

Algebraic Topology · Mathematics 2019-05-01 Benjamin Böhme

Spectral Mackey functors are homotopy-coherent versions of ordinary Mackey functors as defined by Dress. We show that they can be described as excisive functors on a suitable infinity-category, and we use this to show that universal…

Algebraic Topology · Mathematics 2014-06-03 C. Barwick

Binary idempotent semirings govern classical path algebras. Their multiplicative structure is dyadic. We examine whether this restriction is structural or accidental. We define ternary idempotent $\Gamma$-semirings as higher-arity ordered…

Rings and Algebras · Mathematics 2026-02-26 Chandrasekhar Gokavarapu , D. Madhusudhana Rao

We construct a new spectrum of units for a commutative symmetric ring spectrum that detects the difference between a periodic ring spectrum and its connective cover. It is augmented over the sphere spectrum. The homotopy cofiber of its…

Algebraic Topology · Mathematics 2016-05-04 Steffen Sagave

We propose to extend ``invertibility'' to ``regularity'' for categories in general abstract algebraic manner. Higher regularity conditions and ``semicommutative'' diagrams are introduced. Distinction between commutative and…

Mathematical Physics · Physics 2007-05-23 Steven Duplij , Wladyslaw Marcinek

Mackey functors provide the coefficient systems for equivariant cohomology theories. More generally, enriched presheaf categories provide a classification and organization for many stable model categories of interest. Changing enrichments…

Algebraic Topology · Mathematics 2023-12-06 Niles Johnson , Donald Yau

We introduce fusion algebras with not necessarily positive structure constants and without identity element. We prove that they are semisimple when tensored with $\mathbb{C}$ and that their characters satisfy orthogonality relations. Then…

Rings and Algebras · Mathematics 2007-05-23 Michael Cuntz