Companionability of torsion Abelian group actions on fields.

Seminarium: 
Teoria modeli
Osoba referująca: 
Piotr Kowalski (University of Wrocław)
Data: 
środa, 23. Styczeń 2019 - 16:15
Sala: 
604
Opis: 
This is joint work (in progress) with Ozlem Beyarslan. In our previous work (building on my joint work with D. Hoffmann), we showed that Galois actions of finitely generated virtually free groups are companionable. In this work, we deal with the case of infinitely generated torsion Abelian groups. So far, we have obtained partial results suggesting that companionability is closely related with the size of Prufer p-subgroups. I will present first a general model-theoretic background (chains of theories), and then proceed towards the examples of (non)companionable actions in this context.