1. For any r ∈ R 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.