In this thesis , we study some open problems and conjectures about the linear complementarity problem . it consists of the next three aspects : firstly , we study murthys " open problem whether the augmented matrix is a q0 - matrix for an arbitary square matrix a , provide an affirmable answer to this problem , obtain the augmented matrix of a sufficient matrix is a sufficient matrix and prove the graves algorithm can be used to solve linear complementarity problem with bisymmetry po - matrices ; secondly , we study murthys " conjecture about positive semidefinite matrices and provide some sufficient conditions such that a matrix is a positive semidefinite matrix , we also study pang ' s conjecture , obtain two conditions when r0 - matrices and q - matrices are equivelent and some properties about e0 q - matrices ; lastly , we give a counterexample to prove danao ' s conjecture that if a is a po - matrix , a e " a p1 * is false , point out some mistakes of murthys in [ 20 ] , obtain when n = 2 or 3 , a e " a p1 * , i . e . the condition of theorem 3 . 2 of [ 25 ] that a p0 can be deleted and obtain a e " a is an almost e - matrix if a is a co - matrix or column sufficient matrix 本文分为三个部分，主要研究了线性互补问题的几个相关的公开问题以及猜想： ( 1 )研究了murthy等在[ 2 ]中提出的公开问题，即对任意的矩阵a ，其扩充矩阵是否为q _ 0 -矩阵，给出了肯定的回答，得到充分矩阵的扩充矩阵是充分矩阵，并讨论了graves算法，证明了若a是双对称的p _ 0 -矩阵时， lcp ( q ， a )可由graves算法给出； ( 2 )研究了murthy等在[ 6 ]中提出关于半正定矩阵的猜想，给出了半正定矩阵的一些充分条件，并研究了pang ~ -猜想，得到了只r _ 0 -矩阵与q -矩阵的二个等价条件，以及e _ 0 q -矩阵的一些性质； ( 3 )研究了danao在[ 25 ]中提出的danao猜想，即，若a为p _ 0 -矩阵，则，我们给出了反例证明了此猜想当n 4时不成立，指出了murthy等在[ 20 ]中的一些错误，得到n = 2 ， 3时，即[ 25 ]中定理3 . 2中a p _ 0的条件可以去掉。
