Submission date: 18 May 2017

Abstract:

For a group G, we define the notion of a G-kernel and show that the properties of G-kernels are closely related with the existence of a model companion of the theory of Galois actions of G. Using Bass-Serre theory, we show that this model companion exists for virtually free groups generalizing the existing results about free groups and finite groups. We show that the new theories we obtain are not simple and not even NTP_2.

Mathematics Subject Classification: Primary 03C60, Secondary 03C45, 12H10, 20E08

Keywords and phrases:

Full text arXiv 1705.06553: pdf, ps.