3 papers
math.RA2023
An Artin-Schreier-type theory for signatures of hermitian forms over involutions
Nicolas Garrel
In the case of quadratic forms over a field, it is well-known that the prime spectrum of the Witt ring and the space of orderings of the field determine one another, through associ…
math.KT2023
Even Stiefel-Whitney invariants for anti-hermitian quaternionic forms
Nicolas Garrel
We extend all cohomological invariants of similarity classes of quadratic forms to anti-hermitian forms over a quaternion algebra. This uses the fact that such invariants can be li…
math.RA2023
Lambda-operations for hermitian forms over algebras with involution
Nicolas Garrel
The Grothendieck-Witt ring of a field is known to be a -ring, where the -operations are induced by the exterior powers of bilinear spaces. We give a similar construction on t…