Department of Mathematics, Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036, India
Copyright © 2013 Shani Jose and K. C. Sivakumar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Nonnegativity of the Moore-Penrose inverse of a perturbation of the form is considered when . Using a generalized version of the Sherman-Morrison-Woodbury formula, conditions for to be nonnegative are derived. Applications of the results are presented briefly. Iterative versions of the results are also studied.