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Amenability of Universal 2-Grigorchuk group

Roman Muchnik
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Abstract

We consider the universal Grigorchuk 2-group, i.e., the group such that every Grigorchuk 2-group is a quotient. We show that this group has a nice universal representation in the group of all functions f:{0,1,2}^N --> Aut(T_2), where T_2 is a group of automorphism of the binary tree. Finally, we prove that this universal Grigorchuk 2-group is amenable. The proof is an application of the ``Munchhausen trick'' developed by V. Kaimanovich.

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Roman Muchnik. 2005-06-10. Amenability of Universal 2-Grigorchuk group. https://arxiv.org/abs/math/0505572

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