XM Xu, HK Du, X Fang, Y Li - Linear algebra and its applications, 2010 - Elsevier
Let B (H) be the algebra of all bounded linear operators on a complex Hilbert space H. In
1978, Drazin introduced a partial order,⩽∗, on B (H). For A, B∈ B (H), A⩽∗ B if and only if …