3 papers
math.RA2025
Continuity of total signature maps for Azumaya algebras with involution
Vincent Astier, Thomas Unger
In this paper we continue our investigation of signatures of hermitian forms over Azumaya algebras with involution over commutative rings. We show that the approach used in an earl…
math.RA2025
Signature maps from positive cones on algebras with involution
Vincent Astier, Thomas Unger
We introduced positive cones in an earlier paper as a notion of ordering on central simple algebras with involution that corresponds to signatures of hermitian forms. In the curren…
math.RA2018
Galois extensions, positive involutions and an application to unitary space-time coding
Vincent Astier, Thomas Unger
We show that under certain conditions every maximal symmetric subfield of a central division algebra with positive unitary involution will be a Galois extension of the fixe…