# Homomorphism and isomorphism

## Homework Statement

Show that G = {[1 0 [-1 0 [0 -1 [0 1
0 1], 0 -1], 1 0], -1 0]} is a subgroup of GL2[/SUB(Z) isomorphic to {1,-1,i,-i}.

## The Attempt at a Solution

I am clearly sure each element in G can be denoted as {1,-1,i,-i}.
(I can explain why {1,-1,i,-i}, but I will not explain at here.)
so G -> {1,-1,i,-i} is a bijection, so isomorphism.

Is it too simple?