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Related papers: Categorical Milnor squares and K-theory of algebra…

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Fulton defined classes in the Chow group of a quasi-projective scheme $M$ which reduce to its Chern classes when $M$ is smooth. When $M$ has a perfect obstruction theory, Siebert gave a formula for its virtual cycle in terms of its total…

Algebraic Geometry · Mathematics 2020-07-08 Richard P. Thomas

We give some basic properties of Efimov K-theory. In particular, Efimov K-theory is corepresentable, lax symmetric monoidal functor, preserves any small products and sends Milnor squares satisfying base change to cartesian squares.

K-Theory and Homology · Mathematics 2023-03-01 Li He

We introduce the Cuntz-Thomsen picture of $\mathcal{C}$-equivariant Kasparov theory, denoted $\mathrm{KK}^\mathcal{C}$, for a unitary tensor category $\mathcal{C}$ with countably many isomorphism classes of simple objects. We use this…

Operator Algebras · Mathematics 2026-03-16 Sergio Girón Pacheco , Kan Kitamura , Robert Neagu

In this paper, we develop twisted $K$-theory for stacks, where the twisted class is given by an $S^1$-gerbe over the stack. General properties, including the Mayer-Vietoris property, Bott periodicity, and the product structure $K^i_\alpha…

K-Theory and Homology · Mathematics 2007-05-23 Jean-Louis Tu , Ping Xu , Camille Laurent-Gengoux

We introduce the notion of a bounded weight structure on a stable $\infty$-category and use this to prove the natural generalization of Waldhausen's sphere theorem: We show that the algebraic $K$-theory of a stable $\infty$-category with a…

K-Theory and Homology · Mathematics 2019-11-19 Ernest E. Fontes

In this paper, semilocal Milnor $K$-theory of fields is introduced and studied. A strongly convergent spectral sequence relating semilocal Milnor $K$-theory to semilocal motivic cohomology is constructed. In weight 2, the motivic cohomology…

K-Theory and Homology · Mathematics 2022-11-22 Grigory Garkusha

Given a cycle module M with a ring structure we show that the cycle complex with coefficients in M of a smooth scheme of finite type over a field has a A-infinity algebra structure. In the case of Milnor K-theory this gives a homotopy model…

Algebraic Geometry · Mathematics 2009-06-30 Florian Ivorra

This paper extends the notion of geometric control in algebraic K-theory from additive categories with split exact sequences to other exact structures. In particular, we construct exact categories of modules over a Noetherian ring filtered…

K-Theory and Homology · Mathematics 2014-12-12 Gunnar Carlsson , Boris Goldfarb

We introduce and study a class of algebraic stacks with finite inertia in positive and mixed characteristic, which we call tame algebraic stacks. They include tame Deligne-Mumford stacks, and are arguably better behaved than general…

Algebraic Geometry · Mathematics 2007-05-23 Dan Abramovich , Martin Olsson , Angelo Vistoli

In 2006, Restorff completed the classification of all Cuntz-Krieger algebras with finitely many ideals (i.e., those that are purely infinite) up to stable isomorphism. He left open the questions concerning strong classification up to stable…

Operator Algebras · Mathematics 2018-10-08 Toke Meier Carlsen , Gunnar Restorff , Efren Ruiz

The "fundamental theorem" for algebraic $K$-theory expresses the $K$-groups of a Laurent polynomial ring $L[t,t^{-1}]$ as a direct sum of two copies of the $K$-groups of $L$ (with a degree shift in one copy), and certain "nil" groups of…

K-Theory and Homology · Mathematics 2026-05-21 Thomas Huettemann

We describe a procedure to compute the rational nonstable K-groups of A$\mathbb{T}$-algebras. As an application, we show that an A$\mathbb{T}$-algebra is K-stable if and only if it has slow dimension growth.

Operator Algebras · Mathematics 2022-03-03 Apurva Seth , Prahlad Vaidyanathan

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

We classify principal bundles over anti-affine schemes with affine and commutative structural group. We show that this yields the classification of quasi-abelian varieties over a field k (i.e., group k-schemes with no non constant global…

Algebraic Geometry · Mathematics 2008-06-24 Carlos Sancho de Salas , Fernando Sancho de Salas

We prove that the $\infty$-category of motivic spectra satisfies Milnor excision: if $A\to B$ is a morphism of commutative rings sending an ideal $I\subset A$ isomorphically onto an ideal of $B$, then a motivic spectrum over $A$ is…

Algebraic Geometry · Mathematics 2021-08-06 Elden Elmanto , Marc Hoyois , Ryomei Iwasa , Shane Kelly

We develop a theory of Mackey functors on epiorbital categories which simultaneously generalizes the theory of genuine $G$-spectra for a finite group $G$ and the theory of $n$-excisive functors on the category of spectra. Using a new theory…

Algebraic Topology · Mathematics 2017-11-22 Saul Glasman

We compute the Euler characteristic of the structure sheaf of the Brill-Noether locus of linear series with special vanishing at up to two marked points. When the Brill-Noether number $\rho$ is zero, we recover the Castelnuovo formula for…

Algebraic Geometry · Mathematics 2021-02-05 Dave Anderson , Linda Chen , Nicola Tarasca

It is shown that the K-theory of every noetherian base scheme of finite Krull dimension is represented by a strict ring object in the setting of motivic stable homotopy theory. The adjective `strict' is used to distinguish between the type…

Algebraic Topology · Mathematics 2009-07-24 Oliver Röndigs , Markus Spitzweck , Paul Arne Østvær

C.M. Ringel defined Hall algebra associated with the category of representations of a quiver of Dynkin type and gave an explicit description of the structure constants of the corresponding Lie algebra. We utilize functorial properties of…

Representation Theory · Mathematics 2007-05-23 Igor Frenkel , Anton Malkin , Maxim Vybornov

We present an elementary construction of the non-connective algebraic K-theory spectrum associated to an additive category following the contracted functor approach due to Bass. It comes with a universal property that easily allows us to…

K-Theory and Homology · Mathematics 2013-09-05 Wolfgang Lueck , Wolfgang Steimle