Conditions that the product of operators is an EP operator in Hilbert C*-module
Maryam Jalaeian, Mehdi Mohammadzadeh Karizaki, Mahmoud Hassani · Linear and Multilinear Algebra · 2019
The block operator matrix decomposition is used to get new conditions under which the product of two operators is EP while none of them is an EP operator, and the same technique is employed to achieve a new characterization of EP operators. The communication of classes idempotent and normal operators with other common classes of special operators, such as EP, star dagger, bi-EP, and bi dagger operators, are presented, which are derived through matrix operators and Moore–Penrose inverses of operators in the Hilbert C∗-module setting.