English
Equality expressing that strongDownwardInduction(H,s) equals applying H to s with the recursive call to strongDownwardInduction(H,·).
Русский
Равенство, выражающее, что strongDownwardInduction(H,s) равно применению H к s с рекурсивным вызовом к strongDownwardInduction(H,·).
LaTeX
$$$\\text{strongDownwardInduction}(H,s) = H\\left(s,\\lambda t\\; ht\\;\\_,\\ \\text{strongDownwardInduction}(H,t)\\right)$$$
Lean4
theorem strongDownwardInduction_eq {p : Multiset α → Sort*} {n : ℕ}
(H : ∀ t₁, (∀ {t₂ : Multiset α}, card t₂ ≤ n → t₁ < t₂ → p t₂) → card t₁ ≤ n → p t₁) (s : Multiset α) :
strongDownwardInduction H s = H s fun ht _hst => strongDownwardInduction H _ ht := by rw [strongDownwardInduction]