An Artin-Schreier-type theory for signatures of hermitian forms over involutions

Abstract: 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 associated signature maps. We show that a sililar relation holds for hermitian forms over algebras with involution of the first kind, replacing the usual Witt ring with the mixed Witt ring of such an algebra.