Oblique warped products (Q864861)

The author assumes a product manifold \(M= E\times F\) to be equipped with a warped product metric. Therefrom arises by adding a mixed 2-form such that \(E\), \(F\) are no longer orthogonal an oblique warped product metric. The author discusses the existence of such a structure and gives examples: generalized Robertson-Walker space-times and more. Naturally, there emerge connections different from the Levi-Cività one, named after Schouten, Van Kampen, and Vrănceanu.