Theorem

For an matrix , the followings are equivalent:

  1. is invertible;
  2. has only the trivial solution;
  3. ;
  4. is a product of elementary matrices;
  5. is consistent for every ;
  6. has exactly one solution for every ;
  7. ;
  8. The column vectors of are linearly independent;
  9. The row vectors of are linearly independent;
  10. The column vectors of span ;
  11. The row vectors of span ;
  12. The column vectors of is a basis for ;
  13. The row vectors of is a basis for ;
  14. ;
  15. .