Z. Reichstein

activity

20242026

collaborators

7 papers

math.AG2026

Finite abelian subgroups of algebraic groups

Danny Ofek, Zinovy Reichstein, Federico Scavia

Let $k$ be an algebraically closed field, and let $G$ be an algebraic $k$ -group. We study finite abelian $k$ -subgroups $A \subset G$ whose order is not divisible by the characteris…

math.AG2026

Brauer classes not split by genus one curves

Zinovy Reichstein, Federico Scavia

We show that there exist Brauer classes over a field $F$ which are not split by any genus one curve over $F$ . This answers a question of Clark and Saltman.

math.NT2025

The power operation in the Galois cohomology of a reductive group over a number field

Mikhail Borovoi, Zinovy Reichstein, Philippe Gille

For a connected reductive group $G$ over a local or global field $K$ , we define a *diamond* (or *power*) operation $$(Î¾,n)\mapsto Î¾^{\Diamond n}\,\colon\, H^1(K,G)\times {\mathbb…

math.AG2025

Specialization and rigidity

Zinovy Reichstein, Federico Scavia

We describe a general method, originated by Ofer Gabber, for showing that a very general fiber in a family has certain properties. We illustrate this method with concrete examples…

math.AG2024

Linear system of hypersurfaces passing through a Galois orbit

Shamil Asgarli, Dragos Ghioca, Zinovy Reichstein

Let $d$ and $n$ be positive integers, and $E / F$ be a separable field extension of degree $m = (n n + d)$ . We show that if $∣ F ∣ > 2$ , then there exists a point $P\in \mathbb{P}^n…

math.GR2024

Essential Dimension of Small Finite Groups

Dilpreet Kaur, Zinovy Reichstein

We compute the essential dimension of finite groups of order $⩽ 63$ .