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Related papers: Stable A^1-homotopy and R-equivalence

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We prove that, given $\epsilon>0$ and $k\geq 1$, there is an integer $n$ such that the following holds. Suppose $G$ is a finite group and $A\subseteq G$ is $k$-stable. Then there is a normal subgroup $H\leq G$ of index at most $n$, and a…

Logic · Mathematics 2020-02-19 G. Conant , A. Pillay , C. Terry

We prove that in a stable range, the rational cohomology of the moduli space of curves with level structures is the same as that of the ordinary moduli space of curves.

Algebraic Geometry · Mathematics 2025-06-25 Andrew Putman

We give a complete answer to the rationality problem (up to stable $k$-equivalence) for norm one tori $R^{(1)}_{K/k}(\mathbb{G}_m)$ of $K/k$ whose Galois closures $L/k$ are dihedral extensions with the aid of Endo and Miyata [EM75, Theorem…

Algebraic Geometry · Mathematics 2023-11-21 Akinari Hoshi , Aiichi Yamasaki

We prove the Yau-Tian-Donaldson conjecture for cohomogeneity one manifolds, that is, for projective manifolds equipped with a holomorphic action of a compact Lie group with at least one real hypersurface orbit. Contrary to what seems to be…

Algebraic Geometry · Mathematics 2024-06-05 Thibaut Delcroix

Let G be a connected linear algebraic group over an algebraically closed field k, and let H be a connected closed subgroup of G. We prove that the homogeneous variety G/H is a rational variety over k whenever H is solvable, or when dim(G/H)…

Algebraic Geometry · Mathematics 2018-09-24 CheeWhye Chin , De-Qi Zhang

We generalize several basic facts about the motivic sphere spectrum in $\mathbb A^1$-homotopy theory to the category $\mathrm{MS}$ of non-$\mathbb A^1$-invariant motivic spectra over a derived scheme. On the one hand, we show that all the…

Algebraic Geometry · Mathematics 2024-10-23 Marc Hoyois

We prove that if K is an infinite stable field whose generic type has weight 1 then K is separably closed. We also obtain partial results when the generic of K has finite weight and when K is strongly stable.

Logic · Mathematics 2009-10-01 Krzysztof Krupinski , Anand Pillay

A kind of motivic stable homotopy theory of algebras is developed. Explicit fibrant replacements for the $S^1$-spectrum and $(S^1,\mathbb G)$-bispectrum of an algebra are constructed. As an application, unstable, Morita stable and stable…

K-Theory and Homology · Mathematics 2016-08-03 Grigory Garkusha

In the literature, there are two standard rank filtrations on $K$-theory: an ``unstable'' one which is traditionally defined through the homology of $GL_n$, and a ``stable'' one which was defined by Rognes using the simplicial structure on…

K-Theory and Homology · Mathematics 2025-01-06 Jonathan Campbell , Alexander Kupers , Inna Zakharevich

We prove that the homotopy theory of Picard 2-categories is equivalent to that of stable 2-types.

Algebraic Topology · Mathematics 2019-05-01 Nick Gurski , Niles Johnson , Angélica M. Osorno

We give a brief account of the interplay between spectral morphisms, K-theory, and stable ranks in the context of Banach algebras.

Operator Algebras · Mathematics 2010-05-18 Bogdan Nica

We show that separable continuous fields over the unit interval whose fibers are stable Kirchberg algebras that satisfy the universal coefficient theorem in KK-theory and have rational K-theory groups are classified up to isomorphism by…

Operator Algebras · Mathematics 2013-11-05 Rasmus Bentmann , Marius Dadarlat

A theorem is proved to verify incremental stability of a feedback system via a homotopy from a known incrementally stable system. A first corollary of that result is that incremental stability may be verified by separation of Scaled…

Optimization and Control · Mathematics 2024-12-03 Thomas Chaffey , Andrey Kharitenko , Fulvio Forni , Rodolphe Sepulchre

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

We show that if the rotation set of a homeomorphism of the torus is stable under small perturbations of the dynamics, then it is a convex polygon with rational vertices. We also show that such homeomorphisms are $C^0$-generic and have…

Dynamical Systems · Mathematics 2017-03-08 Pierre-Antoine Guihéneuf , Andres Koropecki

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

In this paper, we develop the theory of equivariant motivic homotopy theory, both unstable and stable. While our original interest was in the case of profinite group actions on smooth schemes, we discuss our results in as broad a setting as…

Algebraic Topology · Mathematics 2014-04-08 Gunnar Carlsson , Roy Joshua

In this article we develop the cotangent complex and (co)homology theories for spectral categories. Along the way, we reproduce standard model structures on spectral categories. As applications, we show that the invariants to descend to…

Algebraic Topology · Mathematics 2015-12-24 Jonathan A. Campbell

We study stable rationality properties of conic bundles over rational surfaces.

Algebraic Geometry · Mathematics 2015-03-31 Brendan Hassett , Andrew Kresch , Yuri Tschinkel

Finite suspensions of Koras-Russell threefolds are contractible in A1-homotopy theory.

Algebraic Geometry · Mathematics 2015-12-15 Marc Hoyois , Amalendu Krishna , Paul Arne Østvær