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Related papers: Rigidity in etale motivic stable homotopy theory

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We introduce coefficient systems of pro-\'etale motives and pro-\'etale motivic spectra with coefficients in any condensed ring spectrum and show that they afford the six operations. Over locally \'etale bounded schemes, \'etale motivic…

Algebraic Geometry · Mathematics 2026-04-03 Raphaël Ruimy , Swann Tubach , Sebastian Wolf

We construct a model structure on simplicial profinite sets such that the homotopy groups carry a natural profinite structure. This yields a rigid profinite completion functor for spaces and pro-spaces. One motivation is the \'etale…

Algebraic Topology · Mathematics 2008-12-18 Gereon Quick

In this article, we give a construction of the (un-)stable motivic homotopy category of an algebraic stack in the spirit of Morel-Voevodsky. We prove that this new construction agrees with the stable motivic homotopy category defined by…

Algebraic Geometry · Mathematics 2025-11-04 Neeraj Deshmukh , Felix Sefzig

Let $f : X \rightarrow Y$ be a separable finite surjective map between irreducible normal projective varieties defined over an algebraically closed field, such that the corresponding homomorphism between \'etale fundamental groups $f_* :…

Algebraic Geometry · Mathematics 2022-03-08 Indranil Biswas , Soumyadip Das , A. J. Parameswaran

We construct a well-behaved stable category of modules for a large class of infinite groups. We then consider its Picard group, which is the group of invertible (or endotrivial) modules. We show how this group can be calculated when the…

Group Theory · Mathematics 2019-12-17 Nadia Mazza , Peter Symonds

Let $X$ and $Y$ be irreducible normal projective varieties, of same dimension, defined over an algebraically closed field, and let $f : Y \rightarrow X$ be a finite generically smooth morphism such that the corresponding homomorphism…

Algebraic Geometry · Mathematics 2023-05-15 Indranil Biswas , A. J. Parameswaran

For each prime $p$, we define a $t$-structure on the category $\widehat{S^{0,0}}/\tau\text{-}\mathbf{Mod}_{harm}^b$ of harmonic $\mathbb{C}$-motivic left module spectra over $\widehat{S^{0,0}}/\tau$, whose MGL-homology has bounded…

Algebraic Topology · Mathematics 2020-05-18 Bogdan Gheorghe , Guozhen Wang , Zhouli Xu

We show that conically smooth stratified spaces embed fully faithfully into $\infty$-categories. This articulates a stratified generalization of the homotopy hypothesis proposed by Grothendieck. As such, each $\infty$-category defines a…

Algebraic Topology · Mathematics 2017-03-30 David Ayala , John Francis , Nick Rozenblyum

This is an expository paper providing an overview of the unstable motivic homotopy category using the theory of $(\infty,1)$-categories. In this paper, we examine two constructions in the literature and discuss their equivalence.

Algebraic Topology · Mathematics 2018-10-02 Thomas Brazelton

The apparatus of motivic stable homotopy theory provides a notion of Euler characteristic for smooth projective varieties, valued in the Grothendieck-Witt ring of the base field. Previous work of the first author and recent work of…

Algebraic Geometry · Mathematics 2020-08-26 Marc Levine , Arpon Raksit

We define extension $\infty$-categories for exact $\infty$-categories in terms of bifibrations. Extension $\infty$-categories are invariant when passing to the stable hull, and consequently we show that they form an $\Omega$-spectrum,…

Category Theory · Mathematics 2023-08-29 Erlend D. Børve , Paul Trygsland

Given a good homology theory E and a topological space X, the E-homology of X is not just an E_{*}-module but also a comodule over the Hopf algebroid (E_{*}, E_{*}E). We establish a framework for studying the homological algebra of…

Algebraic Topology · Mathematics 2007-05-23 Mark Hovey

We prove an analogue of the Gabriel--Quillen embedding theorem for exact $\infty$-categories, giving rise to a presentable version of Klemenc's stable envelope of an exact $\infty$-category. Moreover, we construct a symmetric monoidal…

Algebraic Topology · Mathematics 2026-03-23 Marius Nielsen , Christoph Winges

Let $Z\to X$ be a closed immersion of smooth affine schemes over an arbitrary field $k$, and $X^h_Z$ denote the henselization of $X$ along $Z$. For each presheaf $E\colon \mathbf{SH}(k)\to \mathrm{Ab}^\mathrm{op}$ on the stable motivic…

Algebraic Geometry · Mathematics 2020-10-08 A. Druzhinin

Denote by E(Y) the group of homotopy classes of self-homotopy equivalences of a finite-dimensional complex Y. We give a selection of results about certain subgroups of E(Y). We establish a connection between the Gottlieb groups of Y and the…

Algebraic Topology · Mathematics 2007-05-23 M. Arkowitz , G. Lupton , A. Murillo

We analyze stabilization with respect to ${\mathbb P}^1$ in the Morel--Voevodsky unstable motivic homotopy theory. We introduce a refined notion of cellularity (a.k.a., biconnectivity) in various motivic homotopy categories taking into…

Algebraic Geometry · Mathematics 2026-01-26 Aravind Asok , Tom Bachmann , Michael J. Hopkins

Given a small simplicial category $\C$ whose underlying ordinary category is equipped with a Grothendieck topology $\tau$, we construct a model structure on the category of simplicially enriched presheaves on $\C$ where the weak…

Algebraic Topology · Mathematics 2018-11-20 Georgios Raptis , Florian Strunk

Given any pointed CW complex (X,x), it is well known that the fondamental group of X pointed at x is naturally isomorphic to the automorphism group of the functor which associates to a locally constant sheaf on X its fibre at x. The purpose…

Algebraic Topology · Mathematics 2007-05-23 B. Toen

We review the shape theory of $\infty$-topoi, and relate it with the usual cohomology of locally constant sheaves. Additionally, a new localization of profinite spaces is defined which allows us to extend the \'etale realization functor of…

Algebraic Topology · Mathematics 2017-08-15 Joe Berner

We give an algebro-geometric interpretation of $C_2$-equivariant stable homotopy theory by means of the $b$-topology introduced by Claus Scheiderer in his study of $2$-torsion phenomena in \'etale cohomology. To accomplish this, we first…

Algebraic Geometry · Mathematics 2021-02-09 Elden Elmanto , Jay Shah