必要充分条件 meaning in Chinese

necessary and sufficient condition

The necessary and sufficient conditions of law of large numbers
大数定律的必要充分条件
In this paper , the necessary and sufficient conditions for the existence of and the expresssions for the positive definite ( semidefinite ) symmetrizable solutions of inverse problems ax = b are obtained , and the optimal approximation semidefinite symmetrizable solution to given marices is also derived
摘要本文给出了矩阵反问题ax = b具有可对称正定化解与可对称半正定化解的必要充分条件，得到了通解的表达式，同时解决了方程的对称半正定化解对己给矩阵的最佳逼近问题。