2002/10/21 by Marc Lackenby, Lackenby, Marc
Mathematics · #57M10 #57N10 #FOS: Mathematics #Geometric Analysis and Curvature Flows #Geometric Topology (math.GT) #Geometric and Algebraic Topology #Geometry and complex manifolds #math.GT #msc:57M10 #msc:57N10
paper · pdf · doi:10.48550/arxiv.math/0210316
14 pages. Final version, including a new expository section. To appear in Mathematical Research Letters
openalex publication_date 2002/10/21 · arxiv created 2003/11/26 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Let M be a closed orientable 3-manifold with a negatively curved Riemannian metric. Let Mi be a collection of finite regular covers with degree di. (1) If the Heegaard genus of Mi grows more slowly than the square root of di, then Mi has positive first Betti number for all sufficiently large i. (2) The strong Heegaard genus of Mi cannot grow more slowly than the square root of di. (3) If the Heegaard genus of Mi grows more slowly than the fourth root of di, then Mi fibres over the circle for all sufficiently large i. These results provide supporting evidence for the Heegaard gradient conjecture and the strong Heegaard gradient conjecture. As a corollary to (3), we give a necessary and sufficient condition for M to be virtually fibred in terms of the Heegaard genus of its finite covers.