A simple proof is given for a theorem by Milliken and Akdeniz (1977) about the difference of the Moore-Penrose inverses of two positive semi-definite matrices.
@article{urn:eudml:doc:40153, title = {A new proof of the Millinen-Akdeniz theorem.}, journal = {Q\"uestii\'o}, volume = {13}, year = {1989}, pages = {81-82}, mrnumber = {MR1093613}, zbl = {1167.15302}, language = {en}, url = {http://dml.mathdoc.fr/item/urn:eudml:doc:40153} }
Neudecker, Heinz. A new proof of the Millinen-Akdeniz theorem.. Qüestiió, Tome 13 (1989) pp. 81-82. http://gdmltest.u-ga.fr/item/urn:eudml:doc:40153/