I captured this picture from the movie A Beautiful Mind.

I see this is a problem solving for the dimension of a quotient space, so I guess $W$ is assumed to be a subspace of $V$, and let's also assume $V$ is a vector space over $\mathbb{Q}$.

I cannot figure out what $X$ is here. Also, how do I solve this?

p ic

  • $\begingroup$ Look at math.stackexchange.com/questions/284788/… $\endgroup$
    – copper.hat
    Mar 4 '13 at 15:57
  • $\begingroup$ I thought this question was closed as a duplicate of copper.hat's post, but apparently it was reopened. Is it substantially different? $\endgroup$
    – rschwieb
    Nov 19 '13 at 14:47