Note on a matrix-concave function
The authors give a new proof of the inequality \[ \bigl( K' (B + C)^- K \bigr )^+ \geq (K' B^- K)^+ + (K' C^- K)^+ \] where \(B,C\) are positive semidefinite, \(K\) is in the ranges of both \(B,C, ^+\) is the Moore-Penrose inverse and \(^-\) is any generalized inverse.
scientific article; zbMATH DE number 861875