In the above, $V$ is an arbitrary finite vector space over $\mathbb{C}$.
I ask this because I am thinking of an alternative definition of the equivalence of representations.
In the above, $V$ is an arbitrary finite vector space over $\mathbb{C}$.
I ask this because I am thinking of an alternative definition of the equivalence of representations.
Let $V = \mathbb{C}$, so that $GL(V) \cong \mathbb{C}^\times$.
Now, the only subspaces $W$ of $V$ are $V$ itself and $\{ 0 \}$. So the only possibilities for $GL(W)$ are $\mathbb{C}^\times$, or the trivial group.
But $\mathbb{C}^\times$ has subgroups not isomorphic to those (the $n$th roots of unity, for example).
So the claim is not true.