On simultaneous reduction of a pair of oblique projectors to block triangular form
The author discusses a linear algebraic concept which is nevertheless little known to experts in linear algebra. A simple linear algebraic proof is given for the following theorem: Let \(A\) and \(B\) be complex diagonalizable \((n\times{n})\)-matrices, each having exactly two eigenvalues. There exists a subspace \({\mathcal L}\subset\mathbb{C}^n\) of dimension one or two that is invariant with respect to both \(A\) and \(B\).
scientific article; zbMATH DE number 1467867