Bach Flow on Homogeneous Products

Abstract

The qualitative behavior of Bach flow is established on compact four-dimensional locally homogeneous product manifolds. This is achieved by lifting to the homogeneous universal cover and, in most cases, capitalizing on the resultant group structure. The resulting system of ordinary differential equations is carefully analyzed on a case-by-case basis, with explicit solutions found in some cases. The limiting behavior of the metric and the curvature is determined in all cases. The behavior of quotients of ℝ×𝕊³ proves to be the most challenging and interesting.