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Related papers: Tambara functors

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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

Associated to each Tambara functor $T$ is its Nakaoka spectrum $\mathrm{Spec}(T)$, analogous to the Zariski spectrum of a commutative ring. We establish that this topological space is spectral. This result follows from an analysis of the…

Algebraic Topology · Mathematics 2026-02-02 David Chan , Ben Spitz

We show that various flavors of Witt vectors are functorial with respect to multiplicative polynomial laws of finite degree. We then deduce that the $p$-typical Witt vectors are functorial in multiplicative polynomial maps of degree at most…

Algebraic Topology · Mathematics 2020-10-19 Emanuele Dotto , Kristian Moi , Irakli Patchkoria

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

We introduce the theory of biset functors defined on finite categories. Previously, biset functors have been defined on groups, and in that context they are closely related to Mackey functors. Standard examples on groups include…

Representation Theory · Mathematics 2023-07-18 Peter Webb

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

We give, for every finite group G, a combinatorial description of the ring of G-Witt vectors on a polynomial algebra over the integers. Using this description we show that the functor, which takes a ring with trivial action of G to its ring…

Commutative Algebra · Mathematics 2007-05-23 Morten Brun

Free algebras are always free as modules over the base ring in classical algebra. In equivariant algebra, free incomplete Tambara functors play the role of free algebras and Mackey functors play the role of modules. Surprisingly, free…

Algebraic Topology · Mathematics 2024-12-17 Michael A. Hill , David Mehrle , J. D. Quigley

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

A kind of unstable homotopy theory on the category of associative rings (without unit) is developed. There are the notions of fibrations, homotopy (in the sense of Karoubi), path spaces, Puppe sequences, etc. One introduces the notion of a…

K-Theory and Homology · Mathematics 2007-05-23 Grigory Garkusha

In this article we extend evaluations of the Kauffman bracket on regular isotopy classes of knots and links to a variety of functors defined on the category of framed tangles. We show that many such functors exist, and that they correspond…

Geometric Topology · Mathematics 2007-05-23 John Armstrong

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

Let $G$ be a finite group and $\mathbb{K}$ a field of characteristic zero. the ring $R_\mathbb{K}(G)$ of virtual characters of $G$ over $\mathbb{K}$ is naturally endowed with a so-called Grothendieck filtration, with associated graded ring…

Representation Theory · Mathematics 2019-05-03 Beatrice I. Chetard

Traditionally, homotopy groups in $G$-equivariant stable homotopy theory have been graded over $\text{RO}(G)$, the real representation ring of $G$. It is arguably more natural to grade homotopical structures over the Picard group of the…

Algebraic Topology · Mathematics 2025-12-19 Jesse Keyes , Jordan Sawdy

Tambara functors are the analogue of commutative rings in equivariant algebra. Nakaoka defined ideals in Tambara functors, leading to the definition of the Nakaoka spectrum of prime ideals in a Tambara functor. In this work, we continue the…

Algebraic Topology · Mathematics 2026-03-13 David Chan , David Mehrle , J. D. Quigley , Ben Spitz , Danika Van Niel

We show that Hausmann's model of global stable homotopy theory in terms of symmetric spectra is equivalent to the $\infty$-category of spectral Mackey functors in the sense of Barwick on a certain global effective Burnside category. We…

Algebraic Topology · Mathematics 2025-08-18 Tobias Lenz

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 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

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

We refine the invariant on $K_2(A[C_{p_e}]/I_m,(T-1))$ constructed in a previous paper to one which is an isomorphism for all $\lambda$-rings $A$.

K-Theory and Homology · Mathematics 2010-12-07 F. J. B. J. Clauwens