等价于 齐次方程组有非零解

等价于 r(A) < s （维度）

等价于 ｜A｜=0 （只适用于n个n维向量）

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/12bedc76-d725-4fe6-8f76-75a86d1fbfee/image.jpg

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/514f8071-11b8-4938-8492-618c363a4d29/image.jpg