cd
ps
ll
whoami
article
academic
G1T1
linear_algebra
2-inv_mat
3-mat_rank
2-calc
2-classes
rank_down.md
rank_down.md
当$n$阶方阵$A$的秩$R(A)<n$时,则称$A$为降秩矩阵,由此,可逆矩阵又称满秩矩阵,不可逆矩阵又称降秩矩阵