EDB — 269

Exercises

1. [269]We know from [26K]↺↻ that the relation \(n ⊆ m\) is total in \(ℕ\). Prove that

   \begin{equation} ∀ n,m∈ ℕ, n ∈ m \iff (n ⊆ m ∧ n≠ m)\quad . \label{eq:n_ in_ m_ iff_ 2} \end{equation}

   194

   By [24K]↺↻ this implies

   \[ ∀ n,m∈ ℕ, n ⊆ m \iff (n ∈ m \lor n= m)\quad . \]
   Solution 1

   [26B]↺↻