We fix a monster model D of some stable theory and investigate substructures of D which
are existentially closed within the class of substructures equipped with an action of a fixed …

We study model theory of actions of finite groups on substructures of a stable structure. We
give an abstract description of existentially closed actions as above in terms of invariants …

We achieve several results. First, we develop a variant of the theory of absolute Galois
groups in the context of many sorted structures. Second, we provide a method for coding …

ELEMENTARY EQUIVALENCE THEOREM FOR PAC STRUCTURES §1. Introduction.
Pseudo-algebraically closed (PAC) fields were extensively s Page 1 The Journal of Symbolic …

We show that the theory of Galois actions of a torsion Abelian group A is companionable if
and only if, for each prime p, the p-primary part of A is either finite or it coincides with the …

Let G be a finite group. We explore the model-theoretic properties of the class of differential
fields of characteristic zero in m commuting derivations equipped with a G-action by …

We study the embedding property in the category of sorted profinite groups. We introduce a
notion of the sorted embedding property (SEP), analogous to the embedding property for …

arXiv:1905.09741v1 [math.LO] 23 May 2019 Page 1 arXiv:1905.09741v1 [math.LO] 23 May
2019 PAC STRUCTURES IN NUTSHELL DANIEL MAX HOFFMANN† Instytut Matematyki …