Linear sofic representations of amenable algebras

Abstract

We study the notion of linear sofic approximations for algebras, analogous to the concept of sofic representations for groups. We prove that for a finitely generated amenable $K$-algebra with no zero divisors, all linear sofic representations are conjugate. This provides an algebraic analogue to Elek and Szabó's theorem for amenable groups. The proof relies on a "linear monotiling" technique, constructed using a theorem by Brešar, Meshulam and Šemrl on locally linearly dependent operators. Finally, we apply this uniqueness result to the problem of weak stability in the rank metric, showing that the group algebra of an amenable group is weakly stable if and only if the group is residually finite.