Minimaxprinzipe zur Bestimmung der Eigenwerte J-nichtnegativer Operatoren.
Moore-Penrose inverses of Gram matrices leaving a cone invariant in an indefinite inner product space
In this paper we characterize Moore-Penrose inverses of Gram matrices leaving a cone invariant in an indefinite inner product space using the indefinite matrix multiplication. This characterization includes the acuteness (or obtuseness) of certain closed convex cones.