Further results on strongly core orthogonal matrix
Xiaoji Liu, Congcong Wang, Hongxing Wang · Linear and Multilinear Algebra · 2022
Recently, Ferreyra and Malik (Core and strongly core orthogonal matrices. Linear Multilinear Algebra. 2021;1–16. doi:10.1080/03081087.2021.1902923) have proved that if A is strongly core orthogonal to B, then rk(A+B)=rk(A)+rk(B) and (A+B)◯#=A◯#+B◯#. But whether the reverse holds is an open question. In this paper, we solve the problem completely and get some new characterizations of strong core orthogonality.