Lean4
/-- Induction principle starting at a non-zero number.
To use in an induction proof, the syntax is `induction n, hn using Nat.le_induction` (or the same
for `induction'`).
This is an alias of `Nat.leRec`, specialized to `Prop`. -/
@[elab_as_elim]
theorem le_induction {m : ℕ} {P : ∀ n, m ≤ n → Prop} (base : P m m.le_refl)
(succ : ∀ n hmn, P n hmn → P (n + 1) (le_succ_of_le hmn)) : ∀ n hmn, P n hmn :=
@Nat.leRec (motive := P) _ base succ