 We say that \(\bB\) is a homomorphic image of \(\bA\) if there is a homomorphism from \(\bA\) to \(\bB\) which is an onto map from \(A\) to \(B\). An homomorphism from \(\bA\) to \(\bB\) is an isomorphism if it is a one-to-one and onto map from \(A\) to \(B\). If an isomorphism from \(\bA\) to \(\bB\) exists, we say that \(\bA\) and \(\bB\) are isomorphic and that \(\bB\) is an isomorphic image (or a copy) of \(\bA\).