Canonical angles and limits of sequences of EP and co-EP matrices

Let A   be a square complex matrix. Let PP be one of the following properties: (a) A is an EP matrix, (b) the column space of A   is complementary to the column space of A∗A∗, and (c) the orthogonal complement of the column space of A   is the column space of A∗A∗. We study the canonical angles between the column space of A   and the column space of A∗A∗ when A   satisfies property PP. Also, we research the following problem: Let {Am}m=1∞ be a sequence of matrices satisfying property PP that converges to some matrix A. When does A   satisfy property PP?