Transfinite Induction

🅟 Mar 06, 2026

  🅤 Mar 08, 2026

PROP-TIDC. Transfinite Induction.

Let $C$ be a class of ordinals. Suppose

  1. \[0\in C;\]
  2. \[\forall\alpha\in C : \alpha+1\in C;\]
  3. For every limit ordinal $\alpha$,

    \[\alpha\subseteq C \rimp \alpha\in C.\]

Then $C=\Ord$.