activity
20002026
most citedGalois cohomology of reductive algebraic groups over the field of real numbers

17 citations · 63 across the 39 of their papers we have counts for

collaborators

47 papers

math.RA2026

Constructing a complex Lie algebra isomorphic to its complex conjugate but not definable over reals

Mikhail Borovoi, Willem A. de Graaf, Robert M. Guralnick

Following an idea of Demarche and using computer calculations of the authors and ideas of the LLM Claude Fable 5, we construct an explicit 10-dimensional complex two-step nilpotent…

math.GR2026

Non-abelian hypercohomology of a group with coefficients in a crossed module, and Galois cohomology

Mikhail Borovoi

We develop a hypercohomology theory of a group with coefficients in a crossed module, and apply it to define abelianization maps for Galois cohomology of reductive algebraic groups…

math.NT2025

Cup product of inhomogeneous Tate cochains, and Galois cohomology of tori over local fields that split over cyclic extensions

Mikhail Borovoi

In this note we give formulas for cup product in Tate cohomology in terms of inhomogeneous cochains. Using one of these formulas, for a torus T defined over a non-archimedean local…

math.NT2024

Is there a group structure on the Galois cohomology of a reductive group over a global field?

Mikhail Borovoi

Let K be a global field, that is, a number field or a global function field. It is known that the answer to the question in the title over K is "Yes" when K has no real embeddings.…

math.RT2024

The defect of weak approximation for a reductive group over a global field

Mikhail Borovoi, Jean-Louis Colliot-Thélène

We compute the defect of weak approximation for a reductive group G over a global field K in terms of the algebraic fundamental group of G.

math.GR2023

Real non-degenerate two-step nilpotent Lie algebras of dimension eight

Mikhail Borovoi, Bogdan Adrian Dina, Willem A. de Graaf

We classify the non-degenerate two-step nilpotent Lie algebras of dimension 8 over the field of real numbers, using known results over complex numbers. We write explicit structure…