Beschreibung:
<p>We show that all GGS-groups with a non-constant defining vector satisfy the congruence subgroup property. This provides, for every odd prime <inline-formula content-type="math/mathml">
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</inline-formula>, many examples of finitely generated, residually finite, non-torsion groups whose profinite completion is a pro-<inline-formula content-type="math/mathml">
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</inline-formula> group, and among them we find torsion-free groups. This answers a question of Barnea. On the other hand, we prove that the GGS-group with a constant defining vector has an infinite congruence kernel and is not a branch group.</p>