EDB — 25W

Exercises

1. [25W]Having fixed $N\in \mathbb{N}$, consider the ordering $n\subseteq m$ for $n,m\in N$. Since $N\subseteq \mathbb{N}$ is well ordered, then Proposition [26J]↺↻ implies that $(N,\subseteq )$ is well ordered; nonetheless prove directly by induction that $n\subseteq m$ is a well ordering in $N$.

   Solution 1

   [25X]↺↻