Power Series over the Group Ring of a Free Group and Applications to Novikov-shubin Invariants
نویسنده
چکیده
We study power series over the group ring CF of a free group F . We prove that the von Neumann trace maps rational power series over CF to algebraic power series. Using the Riemann-Stieltjes formula, we deduce the rationality and positivity of Novikov-Shubin invariants of matrices over CF .
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