The author introduce the method of applying positive semi-definite quadratic form to prove inequality by giving several examples.
通过给出几个实例，介绍了利用二次型的半正定性证明不等式的方法。
Some equivalent representations of complex positive semi definite matrices are given by using equivalent conditions of positive semi definite of real symmetric matrix.
利用实对称矩阵的半正定之等价条件给出了复正半定矩阵的几个等价条件。
From given eigenvalues and eigenvectors, the inverse eigenvalue problem of symmetric ortho-symmetric positive semi-definite matrices and its optimal approximate problem were considered.
对给定的特征值和对应的特征向量，提出了对称正交对称半正定矩阵逆特征值问题及最佳逼近问题。
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