Philip Dittmann

collaborators

4 papers

math.NT2026

Universally defining subrings in function fields

Nicolas Daans, Philip Dittmann

We establish that all rings of $S$ -integers are universally definable in function fields in one variable over certain ground fields including global and non-archimedean local field…

math.LO2026

Existential theories of henselian valued fields under a formal smoothness assumption

Philip Dittmann

We study existential theories of henselian valued fields of positive characteristic with parameters from a trivially valued subfield. Compared to previous work, we relax perfectnes…

math.LO2026

Composition Ax-Kochen/Ershov principles and tame fields of mixed characteristic

Margarete Ketelsen, Philip Dittmann

We study in which settings we have a composition AKE principle, i.e. when the theory of the coarsening $(K, w)$ and the theory of the induced valuation $(K w, v)$ determine…

math.NT2025

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

Philip Dittmann

We show that each local field $F_{q} ((t))$ of characteristic $p > 0$ is characterised up to isomorphism within the class of all fields of imperfect exponent at most $1$ by (…