Four-free groups and hyperbolic geometry

Abstract

We give new information about the geometry of closed, orientable hyperbolic 3-manifolds with 4-free fundamental group. As an application we show that such a manifold has volume greater than 3.44. This is in turn used to show that if M is a closed orientable hyperbolic 3-manifold such that vol M < 3.44, then H_1(M;Z/2Z) has dimension at most 7.

64 pages, 4 figures. This version corrects an error in the third paragraph of the proof of Lemma 13.3

Cited by in corpus (3)

• Intersections and joins of free groups
• Small isospectral and nonisometric orbifolds of dimension 2 and 3
• Realizable ranks of joins and intersections of subgroups in free groups