9

Here is the question as an exercise in the book Linear Algebra Done Right, Chapter 2

Find all vector spaces that have exactly one basis.

When
  • 521

1 Answers1

9

If $\{v_1,v_2,\dotsc,v_n\}$ is a basis for a vector space $V$, then $\{v_1+v_2,v_2,\dotsc,v_n\}$ is also a basis.

So $V$ should have a basis of one element $v$, now for some nonzero and non-unit element $c$ of the field choose the basis $cv$ for $V$.

So $V$ must be a vector space with dimension one on a field isomorphic to $\mathbb Z_2$.

All vector spaces of this kind are of the form $V=\{0,v\}$ or the trivial one.

Jack M
  • 27,819
  • 7
  • 63
  • 129
k1.M
  • 5,428