English
Equality for the swapped-argument form of the downward strong induction principle.
Русский
Равенство для формы нисходящей сильной индукции с изменённым порядком аргументов.
LaTeX
$$$\\text{strongDownwardInductionOn}(H) = H\\left( s, \\lambda t\\; ht\\;\\_,\\ \\text{strongDownwardInduction}(H,t)\\right)$$$
Lean4
theorem strongDownwardInductionOn_eq {p : Multiset α → Sort*} (s : Multiset α) {n : ℕ}
(H : ∀ t₁, (∀ {t₂ : Multiset α}, card t₂ ≤ n → t₁ < t₂ → p t₂) → card t₁ ≤ n → p t₁) :
s.strongDownwardInductionOn H = H s fun {t} ht _h => t.strongDownwardInductionOn H ht :=
by
dsimp only [strongDownwardInductionOn]
rw [strongDownwardInduction]