A Knebusch trace formula for Azumaya algebras with involution

We establish a trace formula for signatures of hermitian forms over Azumaya algebras with involution, extending Knebusch’s work on symmetric bilinear forms over finite étale extensions of commutative base rings. As an application when the base ring is semilocal, we obtain an exact sequence for total signatures, related to Pfister’s local-global principle and the notion of stability index.