On sectional and Ricci curvatures of semi-Riemannian submersions
This paper deals with semi-Riemannian submersions between two semi-Riemannian manifolds. Sectional and Ricci curvatures are studied for the case of submersions whose fibers are totally geodesic or minimal submanifolds (so-called minimal submersions). Typical results are nonexistence theorems for minimal submersions under certain curvature assumptions. The results are purely local although a number of global examples are given.
scientific article; zbMATH DE number 1057150