Lars Schäfer

Nearly Pseudo-Kähler and Nearly Para-Kähler Manifolds

In this subsection we collect some information on almost ɛ-Hermitian manifolds with a special emphasis on the nearly ɛ-Kahler case.

Second variation for L-minimal Legendrian submanifolds in pseudo-Sasakian manifolds

In this paper we provide the second variation formula for L-minimal Lagrangian submanifolds in a pseudo-Sasakian manifold. We apply it to the case of Lorentzian–Sasakian manifolds and relate the L-stability of L-minimal Legendrian submanifolds in a Sasakian manifold M to their L-stability in an associated Lorentzian–Sasakian structure on M.

Isometric embedding of semi-Riemannian metrics into Minkowski space

Abstract Given a two-dimensional semi-Riemannian metric with positive Gaussian curvature, we construct local isometric embeddings into Minkowski space ℝ2,1. Using reasonable geometric initial conditions, we control the number of solutions and deduce symmetry properties of the solutions.