3 papers
math.KT2026
Categories with conjugation and octagons of Witt groups
David W. Lewis, Jean-Pierre Tignol
A categorical approach is proposed for the construction of 8-periodic chain complexes of Witt groups of categories with duality. Exactness of the resulting sequences is proved unde…
math.KT2025
A new proof of the Artin-Springer theorem in Schur index 2
Anne Quéguiner-Mathieu, Jean-Pierre Tignol
We provide a new proof of the analogue of the Artin-Springer theorem for groups of type that can be represented by similitudes over an algebra of Schur index : an a…
math.GR2018
Outer automorphisms of adjoint groups of type D and non-rational adjoint groups of outer type A
Demba Barry, Jean-Pierre Tignol
For a classical group of type over a field of characteristic different from , we show the existence of a finitely generated regular extension of su…