unfold mergeNodes
α : Type u_1
le : α → α → Bool
not_le_le : ∀ (x y : α), ¬le x y = true → le y x = true
rx : ℕ
xs : List (BinTree α)
ry : ℕ
ys : List (BinTree α)
h₁ : BinTree α
t₁ : List (BinTree α)
h₂ : BinTree α
t₂ : List (BinTree α)
hxs : IsHeapForest' rx (h₁ :: t₁)
hys : IsHeapForest' ry (h₂ :: t₂)
⊢ IsHeapForest' (min rx ry) (mergeNodes le (h₁ :: t₁) (h₂ :: t₂))
α : Type u_1
le : α → α → Bool
not_le_le : ∀ (x y : α), ¬le x y = true → le y x = true
rx : ℕ
xs : List (BinTree α)
ry : ℕ
ys : List (BinTree α)
h₁ : BinTree α
t₁ : List (BinTree α)
h₂ : BinTree α
t₂ : List (BinTree α)
hxs : IsHeapForest' rx (h₁ :: t₁)
hys : IsHeapForest' ry (h₂ :: t₂)
⊢ IsHeapForest' (min rx ry)
    (if h₁.rank < h₂.rank then h₁ :: mergeNodes le t₁ (h₂ :: t₂)
    else
      if h₂.rank < h₁.rank then h₂ :: mergeNodes le t₂ (h₁ :: t₁)
      else
        let merged := combine le h₁ h₂;
        let r := merged.rank;
        if (r != hRank t₁) = true then
          if (r != hRank t₂) = true then merged :: mergeNodes le t₁ t₂ else mergeNodes le (merged :: t₁) t₂
        else if (r != hRank t₂) = true then mergeNodes le t₁ (merged :: t₂) else merged :: mergeNodes le t₁ t₂)