Several theorems in the proceedings only hold under additional, unstated hypotheses. • Theorems 1 and a: Add the hypothesis that → is top-terminating (as defined at the beginning of Section 4). • Theorem 5-10: Add the hypotheses that R is top-terminating and left-linear. • Theorem 17: Incorrect as stated. • Theorem 18: Add the hypothesis that →α = →ωfor all α ≥ ω.