Euler characteristics and 4-manifolds

Contact: Aru Ray (aruray @ mpim-bonn.mpg.de)

We consider the Euler characteristics of closed orientable 2n-manifolds with a given fundamental group G, and highly-connected universal cover. We  strengthen the 4-dimensional Hausmann-Weinberger estimates and extend to higher dimensions.  As an application we obtain new restrictions for non-abelian finite groups arising as fundamental groups of rational homology 4-spheres.