Actions of large finite groups on aspherical manifolds

Abstract: In this paper we study actions of finite groups on closed connected aspherical manifolds. Under some assumptions on the outer automorphism group of the fundamental group of a closed connected aspherical manifold $M$, we prove that the homeomorphism group of $M$ is Jordan, we bound the discrete degree of symmetry of $M$ and obtain a rigidity result, and we study the number of stabilizers of finite group actions on $M$. Thereafter, we show that closed connected aspherical locally homogeneous spaces $H\setminus G/\Gamma$ satisfy the necessary hypothesis on the outer automorphism group of the fundamental group.