English
For all m,n, the natural-number order is equivalent to the Num order: (m:ℕ) ≤ n iff m ≤ n.
Русский
Для всех m,n: порядок по натуральным числаам эквивалентен порядку Num: (m:ℕ) ≤ n ⇔ m ≤ n.
LaTeX
$$$\\forall {m,n : Num}, (m : \\mathbb{N}) \\le n \\Leftrightarrow m \\le n$$$
Lean4
@[norm_cast]
theorem le_to_nat {m n : Num} : (m : ℕ) ≤ n ↔ m ≤ n := by rw [← not_lt]; exact not_congr lt_to_nat