Approximation and continuity of Moore-Penrose inverses of orthogonal row block matrices (Q1015776)

The author obtains several norm inequalities for the difference \(\left[\begin{smallmatrix} A&B\end{smallmatrix} \right]^{\dag}-\left[\begin{smallmatrix} A^\dag\\ B^\dag\end{smallmatrix}\right]\) and uses the obtained norm inequalities to investigate approximation and continuity of \(\left[\begin{smallmatrix} A&B\end{smallmatrix}\right]^\dag\) as \(A^*B\to 0\), where \(|\cdot|\) is a sub-multiplicative matrix norm invariant under the conjugate transpose.