In this paper,firstly,the relationship between the equation of A andA andeigenvalue of A has been searched.By using the characteristic of eigenvalue we get theconditionthat the eigenvalue λ of A may satisfy.This result has characterized thecharacteristic of the eigenvalue of some special matrix,and we have used this result togive a necessary and sufficient condition about generalized projections.Secondly,thisarticle has made a further discussion on the basis of the research of prodessor TianYongge that he has reseached the inertia index of some Hermitian partitioned matrixwhich consist of some orthogonal matrix,the mainly tool is CS decomposition.thepaper has focused on the question which was given by the professor Tian Yongge inliterature [12],and rank and inertia of the combination of some specia operatos hasbeen given. |