-- Mathlib/Data/Ordmap/Ordset.lean
theorem Valid'.glue_aux {l r o₁ o₂} (hl : Valid' o₁ l o₂) (hr : Valid' o₁ r o₂)
    (sep : l.All fun x => r.All fun y => x < y) (bal : BalancedSz (size l) (size r)) :
    Valid' o₁ (@glue α l r) o₂ ∧ size (glue l r) = size l + size r

Proof state:
case refine_3
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
rs : ℕ
rl : Ordnode α
rx : α
rr : Ordnode α
hr : Valid' o₁ (Ordnode.node rs rl rx rr) o₂
sep : All (fun x => All (fun y => x < y) (Ordnode.node rs rl rx rr)) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size (Ordnode.node rs rl rx rr).size
h✝ : ls > rs
v : Valid' o₁ (ll.node' lx lr).eraseMax ↑(findMax' lx lr)
e : (ll.node' lx lr).size = (ll.node' lx lr).eraseMax.size + 1
H :
  (∃ l',
      Raised ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size l' ∧
        BalancedSz l' (Ordnode.node rs rl rx rr).size) ∨
    ∃ r',
      Raised r' (Ordnode.node rs rl rx rr).size ∧
        BalancedSz ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size r'
⊢ (ll.node' lx lr).size + (Ordnode.node rs rl rx rr).size = ll.size + lr.size + 1 + rs

Tactic:
rfl

Result:
no goals

Proof state:
case refine_1
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
rs : ℕ
rl : Ordnode α
rx : α
rr : Ordnode α
hr : Valid' o₁ (Ordnode.node rs rl rx rr) o₂
sep : All (fun x => All (fun y => x < y) (Ordnode.node rs rl rx rr)) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size (Ordnode.node rs rl rx rr).size
h✝ : ls > rs
v : Valid' o₁ (ll.node' lx lr).eraseMax ↑(findMax' lx lr)
e : (ll.node' lx lr).size = (ll.node' lx lr).eraseMax.size + 1
H :
  (∃ l',
      Raised ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size l' ∧
        BalancedSz l' (Ordnode.node rs rl rx rr).size) ∨
    ∃ r',
      Raised r' (Ordnode.node rs rl rx rr).size ∧
        BalancedSz ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size r'
⊢ ∀ (a : α), All (fun y => a < y) (Ordnode.node rs rl rx rr) → nil.Bounded (↑a) o₂

Tactic:
exact fun x h => hr.1.2.to_nil.mono_left (le_of_lt h.2.1)

Result:
no goals

Proof state:
case refine_3
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
rs : ℕ
rl : Ordnode α
rx : α
rr : Ordnode α
hr : Valid' o₁ (Ordnode.node rs rl rx rr) o₂
sep : All (fun x => All (fun y => x < y) (Ordnode.node rs rl rx rr)) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size (Ordnode.node rs rl rx rr).size
h✝ : ¬ls > rs
v : Valid' (↑(rl.findMin' rx)) (rl.node' rx rr).eraseMin o₂
e : (rl.node' rx rr).size = (rl.node' rx rr).eraseMin.size + 1
H :
  (∃ l',
      Raised l' (Ordnode.node ls ll lx lr).size ∧
        BalancedSz l' (rl.findMin' rx, (Ordnode.node (rl.size + rr.size + 1) rl rx rr).eraseMin).2.size) ∨
    ∃ r',
      Raised (rl.findMin' rx, (Ordnode.node (rl.size + rr.size + 1) rl rx rr).eraseMin).2.size r' ∧
        BalancedSz (Ordnode.node ls ll lx lr).size r'
⊢ ((Ordnode.node ls ll lx lr).balanceL (rl.findMin' rx, (Ordnode.node (rl.size + rr.size + 1) rl rx rr).eraseMin).1
        (rl.findMin' rx, (Ordnode.node (rl.size + rr.size + 1) rl rx rr).eraseMin).2).size =
    ls + rs

Tactic:
rw [size_balanceL hl.3 v.3 hl.2 v.2 H, add_assoc, ← e, hr.2.1]

Result:
case refine_3
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
rs : ℕ
rl : Ordnode α
rx : α
rr : Ordnode α
hr : Valid' o₁ (Ordnode.node rs rl rx rr) o₂
sep : All (fun x => All (fun y => x < y) (Ordnode.node rs rl rx rr)) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size (Ordnode.node rs rl rx rr).size
h✝ : ¬ls > rs
v : Valid' (↑(rl.findMin' rx)) (rl.node' rx rr).eraseMin o₂
e : (rl.node' rx rr).size = (rl.node' rx rr).eraseMin.size + 1
H :
  (∃ l',
      Raised l' (Ordnode.node ls ll lx lr).size ∧
        BalancedSz l' (rl.findMin' rx, (Ordnode.node (rl.size + rr.size + 1) rl rx rr).eraseMin).2.size) ∨
    ∃ r',
      Raised (rl.findMin' rx, (Ordnode.node (rl.size + rr.size + 1) rl rx rr).eraseMin).2.size r' ∧
        BalancedSz (Ordnode.node ls ll lx lr).size r'
⊢ (Ordnode.node ls ll lx lr).size + (rl.node' rx rr).size = ls + (rl.size + rr.size + 1)

Proof state:
case nil
α : Type u_1
inst✝ : Preorder α
r : Ordnode α
o₁ : WithBot α
o₂ : WithTop α
hr : Valid' o₁ r o₂
hl : Valid' o₁ nil o₂
sep : All (fun x => All (fun y => x < y) r) nil
bal : BalancedSz nil.size r.size
⊢ Valid' o₁ (nil.glue r) o₂ ∧ (nil.glue r).size = nil.size + r.size

Tactic:
exact ⟨hr, (zero_add _).symm⟩

Result:
no goals

Proof state:
case node.nil
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
hr : Valid' o₁ nil o₂
sep : All (fun x => All (fun y => x < y) nil) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size nil.size
⊢ Valid' o₁ ((Ordnode.node ls ll lx lr).glue nil) o₂ ∧
    ((Ordnode.node ls ll lx lr).glue nil).size = (Ordnode.node ls ll lx lr).size + nil.size

Tactic:
exact ⟨hl, rfl⟩

Result:
no goals

Proof state:
case refine_3
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
rs : ℕ
rl : Ordnode α
rx : α
rr : Ordnode α
hr : Valid' o₁ (Ordnode.node rs rl rx rr) o₂
sep : All (fun x => All (fun y => x < y) (Ordnode.node rs rl rx rr)) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size (Ordnode.node rs rl rx rr).size
h✝ : ls > rs
v : Valid' o₁ (ll.node' lx lr).eraseMax ↑(findMax' lx lr)
e : (ll.node' lx lr).size = (ll.node' lx lr).eraseMax.size + 1
H :
  (∃ l',
      Raised ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size l' ∧
        BalancedSz l' (Ordnode.node rs rl rx rr).size) ∨
    ∃ r',
      Raised r' (Ordnode.node rs rl rx rr).size ∧
        BalancedSz ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size r'
⊢ (((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.balanceR
        ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).2 (Ordnode.node rs rl rx rr)).size =
    ls + rs

Tactic:
rw [size_balanceR v.3 hr.3 v.2 hr.2 H, add_right_comm, ← e, hl.2.1]

Result:
case refine_3
α : Type u_1
inst✝ : Preorder α
o₁ : WithBot α
o₂ : WithTop α
ls : ℕ
ll : Ordnode α
lx : α
lr : Ordnode α
hl : Valid' o₁ (Ordnode.node ls ll lx lr) o₂
rs : ℕ
rl : Ordnode α
rx : α
rr : Ordnode α
hr : Valid' o₁ (Ordnode.node rs rl rx rr) o₂
sep : All (fun x => All (fun y => x < y) (Ordnode.node rs rl rx rr)) (Ordnode.node ls ll lx lr)
bal : BalancedSz (Ordnode.node ls ll lx lr).size (Ordnode.node rs rl rx rr).size
h✝ : ls > rs
v : Valid' o₁ (ll.node' lx lr).eraseMax ↑(findMax' lx lr)
e : (ll.node' lx lr).size = (ll.node' lx lr).eraseMax.size + 1
H :
  (∃ l',
      Raised ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size l' ∧
        BalancedSz l' (Ordnode.node rs rl rx rr).size) ∨
    ∃ r',
      Raised r' (Ordnode.node rs rl rx rr).size ∧
        BalancedSz ((Ordnode.node (ll.size + lr.size + 1) ll lx lr).eraseMax, findMax' lx lr).1.size r'
⊢ (ll.node' lx lr).size + (Ordnode.node rs rl rx rr).size = ll.size + lr.size + 1 + rs