12 citations · 26 across the 9 of their papers we have counts for
13 papers
Degree relative invariant for unitary involutions
Demba Barry, Alexandre Masquelein, Anne Quéguiner-Mathieu
Using the Rost invariant for non split simply connected groups, we define a relative degree cohomological invariant for pairs of orthogonal or unitary involutions having isomor…
Minimal quadratic forms for the function field of a conic in characteristic
Adam Chapman, Anne Quéguiner-Mathieu
In this note, we construct explicit examples of -minimal quadratic forms of dimension and , where is the function field of a conic over a field of characteris…
Decomposability of orthogonal involutions in degree 12
Anne Quéguiner-Mathieu, Jean-Pierre Tignol
A theorem of Pfister asserts that every -dimensional quadratic form with trivial discriminant and trivial Clifford invariant over a field of characteristic different from d…
The canonical quadratic pair on a Clifford algebra and triality
Andrew Dolphin, Anne Quéguiner-Mathieu
We define a canonical quadratic pair on the Clifford algebra of an algebra with quadratic pair over a field. This allows us to extend to the characteristic 2 case the notion of tri…
Orthogonal involutions on central simple algebras and function fields of Severi-Brauer varieties
Anne Quéguiner-Mathieu, Jean-Pierre Tignol
An orthogonal involution on a central simple algebra , after scalar extension to the function field of the Severi--Brauer variety of , is adjoint to a qu…
Critical varieties and motivic equivalence for algebras with involution
Charles De Clercq, Anne Quéguiner-Mathieu, Maksim Zhykhovich
Motivic equivalence for algebraic groups was recently introduced in [9], where a characterization of motivic equivalent groups in terms of higher Tits indexes is given. As a conseq…
Outer automorphisms of classical algebraic groups
Anne Quéguiner-Mathieu, Jean-Pierre Tignol
The so-called Tits class, associated to an adjoint absolutely almost simple algebraic group, provides a cohomological obstruction for this group to admit an outer automorphism. If…
Symplectic Involutions, quadratic pairs and function fields of conics
Andrew Dolphin, Anne Quéguiner-Mathieu
In this paper we study symplectic involutions and quadratic pairs that become hyperbolic over the function field of a conic. In particular, we classify them in degree 4 and deduce…
The Arason invariant of orthogonal involutions of degree 12 and 8, and quaternionic subgroups of the Brauer group
Anne Quéguiner-Mathieu, Jean-Pierre Tignol
Using the Rost invariant for torsors under Spin groups one may define an analogue of the Arason invariant for certain hermitian forms and orthogonal involutions. We calculate this…
Involutions, odd-degree extensions and generic splitting
Jodi Black, Anne Quéguiner-Mathieu
Let be a quadratic form over a field and let be a field extension of of odd degree. It is a classical result that if is isotropic (resp. hyperbolic) then …
Pfister's Theorem for orthogonal involutions of degree 12
Skip Garibaldi, Anne Quéguiner-Mathieu
We use the fact that a projective half-spin representation of has an open orbit to generalize Pfister's result on quadratic forms of dimension 12 in to orthogonal…
A generic characterization of direct summands for orthogonal involutions
Anne Quéguiner-Mathieu
The `transcendental methods' in the algebraic theory of quadratic forms are based on two major results, proved in the 60's by Cassels and Pfister, and known as the representation a…
Restricting the Rost Invariant to the Center
Skip Garibaldi, Anne Quéguiner-Mathieu
For simple simply connected algebraic groups of classical type, Merkurjev, Parimala, and Tignol gave a formula for the restriction of the Rost invariant to torsors induced from the…