Characterising local fields of positive characteristic by Galois theory and the Brauer group

Abstract

We show that each local field ${\mathbb{F}}_q((t))$ of characteristic $p>0$ is characterised up to isomorphism within the class of all fields of imperfect exponent at most $1$ by (certain small quotients of) its absolute Galois group together with natural axioms concerning the $p$-torsion of its Brauer group. This complements previous work by Efrat-Fesenko, who analysed fields whose absolute Galois group is isomorphic to that of a local field of characteristic $p$.

Numerous improvements to the presentation. Version accepted for publication