id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
ejpam-1624	Xie, Tao; Zuo, Kezheng	The Drazin inverses of Combinations of Two idempotents	2012	12	.pdf	application/pdf	4496	256	87	Direct calculations show that aP + bQ+ cPQ+ dQP =      bI (b+ d)Q12 bQ′13 bQ′′13 0 aI (b+ c)Q′23 (b+ c)Q′′23 0 0 bI bQ′′33 0 0 0 0      It is clear that the condition a, b 6= 0 implies the invertibility of    bI (b+ d)Q12 bQ′13 0 aI (b+ c)Q′23 0 0 − b+c ab Q′23 0 0 1 b I     2   bQ′′13 (b+ c)Q′′23 bQ′′33    =     1 b Q′′13 − [ (b+c)(b+d) ab2 + 2 b ]Q′13Q′′33 −( 1 a + c ab )Q′′23 1 b Q′′33     .	cache/ejpam-1624.pdf	txt/ejpam-1624.txt