In this paper, the connections between model theory and the theory of infinite permutation groups (see [11]) are used to study the n-existence and the n-uniqueness for n-amalgamation problems of… (More)

In this poster we show several applications of results of group cohomology to finite covers. In the first part we give a criterion for determining if a given profinite Gmodule is the kernel for a… (More)

For Ω an infinite set, k ≥ 2 and W the set of k-sets from Ω, there is a natural closed permutation group Γk which is a non-split extension 0 → Z2 → Γk → Sym(Ω)→ 1. We classify the closed subgroups of… (More)

Let W be a first-order structure and ρ be an Aut(W )-congruence on W . In this paper we define the almost-free finite covers of W with respect to ρ, and we show how to construct them. These are a… (More)

Let W be a first-order structure and ρ be an Aut(W )-congruence on W . In this paper we define the almost-free finite covers of W with respect to ρ, and we show how to construct them. These are a… (More)