THE DRAZIN INVERSES OF PRODUCTS AND DIFFERENCES OF PROJECTIONS IN A C*-ALGEBRA

YUAN LI
2009 Journal of the Australian Mathematical Society  
For two given projections p and q in a C * -algebra, we investigate how to express the Drazin inverses of the product pq and the difference p − q, and give applications. As a special case, we obtain the results of [C. Y. Deng, 'The Drazin inverses of products and differences of orthogonal projections', J. Math. Anal. Appl. 335 (2007) 64-71], with considerably simpler proofs. 2000 Mathematics subject classification: primary 15A09; secondary 46L99, 65F20.
doi:10.1017/s1446788708000451 fatcat:ozvtey3kkvd7nlt3p2uu2gk3ia