3 papers
math.LO2025
Definable ranks
Lothar Sebastian Krapp, Salma Kuhlmann, Lasse Vogel
We introduce the notion of the definable rank of an ordered field, ordered abelian group and ordered set, respectively. We study the relation between the definable rank of an order…
math.LO2024
Definable henselian valuations on dp-minimal real fields
Lothar Sebastian Krapp, Salma Kuhlmann, Lasse Vogel
We give an explicit algebraic characterisation of all definable henselian valuations on a dp-minimal real field. Additionally we characterise all dp-minimal real fields that admit…
math.RA2024
Automorphisms and derivations on algebras endowed with formal infinite sums
Vincent Bagayoko, Lothar Sebastian Krapp, Salma Kuhlmann +2
We establish a correspondence between automorphisms and derivations on certain algebras of generalised power series. In particular, we describe a Lie algebra of derivations on a fi…