cases children with | heap nodes =>
dsimp at *
cases bt with | mk rt =>
dsimp at rt
apply IsHeapForest'_of_IsRankedTree (r := 1)
. simp
. assumption
case mk.cons
α : Sort ?u.30046
le : α → α → Bool
not_le_le : ∀ (x y : α), ¬le x y = true → le y x = true
le_trans : ∀ (x y z : α), le x y = true → le y z = true → le x z = true
le_rfl : ∀ (z : α), le z z = true
α✝ : Type u_1
val : α✝
rank : ℕ
children : Heap α✝
bt : IsBinTree { val := val, rank := rank, children := children }
lt : 0 < rank
h₁ : IsHeapForest' rank []
⊢ IsHeap children
no goals