ABSTRACT
In Chapter 11, you studied isomorphisms. You saw there that two groups (G, ∘) and (H, ⋅) were isomorphic if there was a bijection f: G → H such that for all x, y ∈ G, f(x ∘ y) = f(x) ⋅ f(y).
In this chapter you will study homomorphisms. The difference between a homomorphism and an isomorphism is that the function f is no longer required to be a bijection.
