# Article

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Keywords:
construction scheme; Knaster hierarchy; Cohen reals
Summary:
We investigate the question of whether or not an amenable subgroup of the permutation group on \$\mathbb{N}\$ can have a unique invariant mean on its action. We extend the work of M. Foreman (1994) and show that in the Cohen model such an amenable group with a unique invariant mean must fail to have slow growth rate and a certain weakened solvability condition.
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