Nine equivalent conditions of real idempotent matrix are given and proved,and one equivalent condition of real symmetric idempotent matrix is also given in this paper.
郭华.实幂等矩阵的几个等价条件[J].重庆工商大学学报(自然科学版),2001,(2): GUO Hua. Several Equivalent Conditions of Real Idempotent Matrix[J]. Journal of Chongqing Technology and Business University(Natural Science Edition),2001,(2):