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Related papers: Norms and Hermitian $\mathrm{K}$-Theory

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We construct a theory of motivic cohomology for quasi-compact, quasi-separated schemes of equal characteristic, which is related to non-connective algebraic $K$-theory via an Atiyah--Hirzebruch spectral sequence, and to \'etale cohomology…

K-Theory and Homology · Mathematics 2026-03-30 Elden Elmanto , Matthew Morrow

We prove that for the action of a finite constant group scheme, equivariant algebraic $K$-theory is represented by a colimit of Grassmannians in the equivariant motivic homotopy category. Using this result we show that the set of…

Algebraic Geometry · Mathematics 2025-08-15 K. Arun Kumar , Girja S Tripathi

Let $kq$ denote the very effective cover of Hermitian K-theory. We apply the $kq$-based motivic Adams spectral sequence, or $kq$-resolution, to computational motivic stable homotopy theory. Over base fields of characteristic not two, we…

Algebraic Topology · Mathematics 2020-12-29 Dominic Leon Culver , J. D. Quigley

We construct a ``logarithmic'' cohomology operation on Morava E-theory, which is a homomorphism defined on the multiplicative group of invertible elements in the ring E^0(K) of a space K. We obtain a formula for this map in terms of the…

Algebraic Topology · Mathematics 2008-12-05 Charles Rezk

We show how methods from K-theory of operator algebras can be applied in a completely algebraic setting to define a bivariant, matrix-stable, homotopy-invariant, excisive K-theory of algebras over a fixed unital ground ring H, kk_*(A,B),…

K-Theory and Homology · Mathematics 2011-08-03 Guillermo Cortiñas , Andreas Thom

We construct geometric models for classifying spaces of linear algebraic groups in G-equivariant motivic homotopy theory, where G is a tame group scheme. As a consequence, we show that the equivariant motivic spectrum representing the…

K-Theory and Homology · Mathematics 2020-09-16 Marc Hoyois

We solve affirmatively the homotopy limit problem for $K$-theory over fields of finite virtual cohomological dimension. Our solution employs the motivic slice filtration and the first motivic Hopf map.

K-Theory and Homology · Mathematics 2017-01-24 Oliver Röndigs , Markus Spitzweck , Paul Arne Østvær

The aim of this paper is to connect two important and apparently unrelated theories: motivic homotopy theory and ramification theory. We construct motivic homotopy categories over a qcqs base scheme $S$, in which cohomology theories with…

Algebraic Geometry · Mathematics 2025-04-04 Junnosuke Koizumi , Hiroyasu Miyazaki , Shuji Saito

We extend homological perturbation theory to encompass algebraic structures governed by operads and cooperads. The main difficulty is to find a suitable notion of algebra homotopy that generalizes to algebras over operads O. To solve this…

Algebraic Topology · Mathematics 2016-01-20 Alexander Berglund

We advance the understanding of K-theory of quadratic forms by computing the slices of the motivic spectra representing hermitian K-groups and Witt-groups. By an explicit computation of the slice spectral sequence for higher Witt-theory, we…

K-Theory and Homology · Mathematics 2017-05-31 Oliver Röndigs , Paul Arne Østvær

Commutative $d$-torsion $K$-theory is a variant of topological $K$-theory constructed from commuting unitary matrices of order dividing $d$. Such matrices appear as solutions of linear constraint systems that play a role in the study of…

Algebraic Topology · Mathematics 2024-06-19 Cihan Okay

A general method of producing correspondences and spectral categories out of symmetric ring objects in general categories is given. As an application, stable homotopy theory of spectra $SH$ is recovered from modules over a commutative…

Algebraic Topology · Mathematics 2023-10-03 Grigory Garkusha

We formulate and prove a Conner-Floyd isomorphism for the algebraic K-theory of arbitrary qcqs derived schemes. To that end, we study a stable $\infty$-category of non-$\mathbb A^1$-invariant motivic spectra, which turns out to be…

Algebraic Geometry · Mathematics 2024-02-15 Toni Annala , Marc Hoyois , Ryomei Iwasa

We combine several mini miracles to achieve an elementary understanding of infinite loop spaces and very effective spectra in the algebro-geometric setting of motivic homotopy theory. Our approach combines $\Gamma$-spaces and framed…

Algebraic Geometry · Mathematics 2022-04-22 Grigory Garkusha , Ivan Panin , Paul Arne Østvær

In joint work with Elmanto, Hoyois, Khan and Sosnilo, we computed infinite $\mathbb{P}^1$-loop spaces of motivic Thom spectra, using the technique of framed correspondences. This result allows us to express non-negative…

K-Theory and Homology · Mathematics 2023-06-22 Maria Yakerson

We introduce a theory of motivic cohomology for quasi-compact quasi-separated schemes, which generalises the construction of Elmanto--Morrow in the case of schemes over a field. Our construction is non-$\mathbb{A}^1$-invariant in general,…

Algebraic Geometry · Mathematics 2025-07-22 Tess Bouis

For a finite group $G$, we construct a simplified model for the $G$-symmetric monoidal $G$-$\infty$-category of rational $G$-spectra. Using this model, we classify $\mathcal{I}$-normed algebras in rational $G$-spectra for a given indexing…

Algebraic Topology · Mathematics 2026-04-30 Giorgi Tigilauri

In this paper we study the "holomorphic K-theory" of a projective variety, which is defined in terms of the homotopy type of spaces of holomorphic maps from the variety to Grassmannians and loop groups. This theory was introduced by Lawson,…

Algebraic Topology · Mathematics 2007-05-23 Ralph L. Cohen , Paulo Lima-Filho

We study homotopy-coherent commutative multiplicative structures on equivariant spaces and spectra. We define N-infinity operads, equivariant generalizations of E-infinity operads. Algebras in equivariant spectra over an N-infinity operad…

Algebraic Topology · Mathematics 2015-07-01 Andrew J. Blumberg , Michael A. Hill

We define an unstable equivariant motivic homotopy category for an algebraic group over a Noetherian base scheme. We show that equivariant algebraic $K$-theory is representable in the resulting homotopy category. Additionally, we establish…

Algebraic Topology · Mathematics 2015-10-19 Jeremiah Heller , Amalendu Krishna , Paul Arne Ostvaer