Property (T) for Kac-Moody groups over rings

2017/08/07 by Mikhail A. Ershov, Ershov, Mikhail, Ashley Rall +3
Mathematics · #Algebraic structures and combinatorial models #Advanced Operator Algebra Research #Advanced Algebra and Geometry

paper · pdf · doi:10.48550/arxiv.1708.01968

Abstract

Let R be a finitely generated commutative ring with 1, let A be an indecomposable 2-spherical generalized Cartan matrix of size at least 2 and M=M(A) the largest absolute value of a non-diagonal entry of A. We prove that there exists an integer n=n(A) such that the Kac-Moody group G_A(R) has property (T) whenever R has no proper ideals of index less than n and all positive integers less than or equal to M are invertible in R.

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