On the integral Hodge conjecture for real varieties, I

O Benoist, O Wittenberg - Inventiones mathematicae, 2020 - Springer
We formulate the “real integral Hodge conjecture”, a version of the integral Hodge
conjecture for real varieties, and raise the question of its validity for cycles of dimension 1 on …

Invariants of algebraic groups and retract rationality of classifying spaces

A Merkurjev - Algebraic groups: structure and actions, 2017 - books.google.com
Let G be an algebraic group over a field F, V a generically free representation of G (ie, the
stabilizer of the generic point in V is trivial) and U⊂ V a G-equivariant open subset such that …

Cohomological invariants of algebraic tori

S Blinstein, A Merkurjev - Algebra & Number Theory, 2013 - msp.org
Let G be an algebraic group over a field F. As defined by Serre, a cohomological invariant of
G of degree n with values in ℚ∕ ℤ (j) is a functorial-in-K collection of maps of sets Tors G …

Cohomological invariants for quadratic forms over local rings

JA Jacobson - Mathematische Annalen, 2018 - Springer
Let A be local ring in which 2 is invertible and let n be a non-negative integer. We show that
the nth cohomological invariant of quadratic forms is a well-defined homomorphism from the …

Versal torsors and retracts

AS Merkurjev - Transformation Groups, 2020 - Springer
Let G be an algebraic group over F and pa prime integer. We introduce the notion of ap-
retract rational variety and prove that if Y→ X is ap-versal G-torsor, then BG is a stable p …

A generalization of Serre's condition with applications to the finiteness of unramified cohomology

IA Rapinchuk - Mathematische Zeitschrift, 2019 - Springer
In this paper, we introduce a condition (F _m'F m′) on a field K, for a positive integer m, that
generalizes Serre's condition (F) and which still implies the finiteness of the Galois …

A Bloch–Ogus theorem for henselian local rings in mixed characteristic

J Schmidt, F Strunk - Mathematische Zeitschrift, 2023 - Springer
We show a conditional exactness statement for the Nisnevich Gersten complex associated
to an A 1-invariant cohomology theory with Nisnevich descent for smooth schemes over a …

Equivariant semi-topological invariants, Atiyah's 𝐾𝑅-theory, and real algebraic cycles

J Heller, M Voineagu - Transactions of the American Mathematical Society, 2012 - ams.org
We establish an Atiyah-Hirzebruch type spectral sequence relating real morphic
cohomology and real semi-topological $ K $-theory and prove it to be compatible with the …

Smooth weight structures and birationality filtrations on motivic categories

M Bondarko, D Kumallagov - St. Petersburg Mathematical Journal, 2022 - ams.org
In various triangulated motivic categories, a vast family of aisles (these are certain classes of
objects) is introduced. These aisles are defined in terms of the corresponding “motives”(or …

Stable 𝔸1-connectivity over a base

AE Druzhinin - Journal für die reine und angewandte Mathematik …, 2022 - degruyter.com
Morel's stable connectivity theorem states the vanishing of the sheaves of the negative
motivic homotopy groups π¯ is⁢(Y) and π¯ i+ j, js⁢(Y), i< 0, in the stable motivic homotopy …