Concept
Groupe de Witt
Publications associées (13)
On the Grothendieck-Serre conjecture for classical groups
We prove some new cases of the Grothendieck-Serre conjecture for classical groups. This is based on a new construction of the Gersten-Witt complex for Witt groups of Azumaya algebras with involution on regular semilocal rings, with explicit second residue ...
WILEY2022Serre-Tate theory for Calabi-Yau varieties
Classical Serre-Tate theory describes deformations of ordinary abelian varieties. It implies that every such variety has a canonical lift to characteristic zero and equips the base of its universal deformation with a Frobenius lifting and canonical multipl ...
WALTER DE GRUYTER GMBH2021Automorphisms of even unimodular lattices and equivariant Witt groups
We characterize the irreducible polynomials that occur as the characteristic polynomial of an automorphism of an even unimodular lattice of a given signature, generalizing a theorem of Gross and McMullen. As part of the proof, we give a general criterion i ...
EUROPEAN MATHEMATICAL SOC2020Invariant forms on irreducible modules of simple algebraic groups
Let G be a simple linear algebraic group over an algebraically dosed field K of characteristic p >= 0 and let V be an irreducible rational G-module with highest weight A. When is self-dual, a basic question to ask is whether V has a non-degenerate G-invari ...
Elsevier2017Hermitian Categories, Extension Of Scalars And Systems Of Sesquilinear Forms
Eva Bayer Fluckiger, Daniel Arnold Moldovan
We prove that the category of systems of sesquilinear forms over a given hermitian category is equivalent to the category of unimodular 1-hermitian forms over another hermitian category. The sesquilinear forms are not required to be unimodular or defined o ...
Pacific Journal Mathematics2014Hermitian Forms over Algebras with Involution and Hermitian Categories
This thesis is concerned with the algebraic theory of hermitian forms. It is organized in two parts. The first, consisting of the first two chapters, deals with some descent properties of unimodular hermitian forms over central simple algebras with involut ...
EPFL2012Descent properties of hermitian Witt groups in inseparable extensions
Eva Bayer Fluckiger, Daniel Arnold Moldovan
Let k be a field of characteristic ≠2, A be a central simple algebra with involution σ over k and W(A,σ) be the associated Witt group of hermitian forms. We prove that for all purely inseparable extensions L of k, the canonical map rL/k:W(A,σ)⟶W(AL,σL) is ...
Springer Verlag2011