1. For any rR and any positive integer n,
φ(nr) = nφ(r) and φ(rn) = (φ(r))n.
2. φ(A) is a subring of S.
3. If A is an ideal and is onto S, then φ(A) is an ideal of S.
4. φ-1(B) is an ideal of R.
5. If R is commutative, then φ(R) is commutative.