English
For all α with preorder and decidable ≤, and all x, insert' x t equals insertWith id x t.
Русский
Для всех α с порядком и разрешимой ≤, и для всех x, insert' x t равно insertWith id x t.
LaTeX
$$$\\forall x,\\ t,\\ \\mathrm{insert'} x t = \\mathrm{insertWith}(\\mathrm{id}) x t$$$
Lean4
theorem insert'_eq_insertWith [DecidableLE α] (x : α) : ∀ t, insert' x t = insertWith id x t
| nil => rfl
| node _ l y r => by unfold insert' insertWith; cases cmpLE x y <;> simp [insert'_eq_insertWith]