4 papers
Decomposing the automorphism group of the surreal numbers
Elliot Kaplan, Lothar Sebastian Krapp, Michele Serra
We study the automorphism group of the field of surreal numbers. Our main structure theorem presents a decomposition of this group into a product of five significant factors. Using…
Automorphisms of valued Hahn groups
Salma Kuhlmann, Michele Serra
Hahn groups endowed with the canonical valuation play a fundamental role in the classification of valued abelian groups. In this paper we study the group of valuation (respectively…
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…
Generalised power series determined by linear recurrence relations
Lothar Sebastian Krapp, Salma Kuhlmann, Michele Serra
In 1882, Kronecker established that a given univariate formal Laurent series over a field can be expressed as a fraction of two univariate polynomials if and only if the coefficien…