Abstract Algebra: a homomorphism map from units to Z/4Z?

Question

Can u give me a homomorphism map from {1, -1, i, -i} to Z/4Z?

Z is the symbol for integers, i is root -1

thanks

Answer 1

i^j -->j for j = 0, 1, 2, 3.

That's the idea behind the prior answer.

Answer 2

{1, i, -1, -i} --> {0, 1, 2, 3}