Definition by Transfinite Recursion Cambridge II Logic And Set Theory Equivalence of Zorn, AC, and Well-Ordering Cambridge II Logic And Set Theory Every Non-empty Set of Ordinals Has a Least Element Cambridge II Logic And Set Theory Consistent Extension Lemma Cambridge II Logic And Set Theory Initial Segments of Well-orderings Cambridge II Logic And Set Theory Division Algorithm for Normal Functions Cambridge II Logic And Set Theory Totality of the Comparison Order Cambridge II Logic And Set Theory Decidability Theorem Cambridge II Logic And Set Theory