On Bach flat warped product Einstein manifolds (Q387717)

This paper presents an interesting study of a special class of compact warped product Einstein manifolds, those with vanishing Bach tensor. It is proven that a manifold from this class of dimension \(n \geq 4\) is either Einstein or a finite quotient of a warped product with an \((n-1)\)-dimensional Einstein fiber. In case \(n=4\) the fiber has constant curvature.