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Abstract: We shall study a class of extreme sofic approximations, that cannot be decomposed into two different sofic approximations. A result of Elek and Szabo can be restated with this language as: a group is amenable iff every sofic approx- imation is indecomposable. We shall construct examples of indecomposable sofic approximations for residually finite groups and if time allows, we shall generalize this to residually amenable groups.
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