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

Let A be a square complex matrix. Let P 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, and (c) the orthogonal complement of the column space of A is the column space of A. We study the canonical angles between the column space of A and the column space of A when A satisfies property P. Also, we research the following problem: Let { Am}m= 1¿ be a sequence of matrices satisfying property P that converges to some matrix A. When does A satisfy property P? © 2012 Elsevier Inc. All rights reserved.