Let P and Q be two idempotents on a Hilbert space. In this note, we prove that the invertibility of the linear combination $\lambda_{1}P + \lambda_{2}Q$ is independent of the choice of $\lambda_{i}$, ...

In a previous work, the author showed how linear combinations of the orthogonal components of the Cramer-von Mises statistic could be used to test fit to a fully specified distribution function. In ...