have hl (acc : Array (Literal (PosFin n)) × Array Assignment × Bool)
  (ih : ∀ l : Literal (PosFin n), l ∈ acc.1.data → l ∈ f.rupUnits.data ∨ l ∈ units)
  (unit : Literal (PosFin n)) (unit_in_units : unit ∈ units) :
  ∀ l : Literal (PosFin n), l ∈ (insertUnit acc unit).1.data → (l ∈ f.rupUnits.data ∨ l ∈ units) := by
  intro l hl
  rw [insertUnit] at hl
  simp only [Prod.mk.eta] at hl
  split at hl
  . exact ih l hl
  . simp only [Array.push_data, List.mem_append, List.mem_singleton] at hl
    rcases hl with l_in_acc | l_eq_unit
    . exact ih l l_in_acc
    . rw [l_eq_unit]
      exact Or.inr unit_in_units
n : Nat
f : DefaultFormula n
units : List (Literal (PosFin n))
c : DefaultClause n
h :
  some c ∈ f.clauses.data ∨
    (∃ a,
        (a, false) ∈ (List.foldl insertUnit (f.rupUnits, f.assignments, false) units).fst.data ∧ unit (a, false) = c ∨
          (a, true) ∈ (List.foldl insertUnit (f.rupUnits, f.assignments, false) units).fst.data ∧ unit (a, true) = c) ∨
      ∃ a, (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = c ∨ (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = c
hb : ∀ (l : Literal (PosFin n)), l ∈ (f.rupUnits, f.assignments, false).fst.data → l ∈ f.rupUnits.data ∨ l ∈ units
⊢ (∃ a, (a, false) ∈ units ∧ Clause.unit (a, false) = c ∨ (a, true) ∈ units ∧ Clause.unit (a, true) = c) ∨
    some c ∈ f.clauses.data ∨
      (∃ a, (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = c ∨ (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = c) ∨
        ∃ a, (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = c ∨ (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = c
n : Nat
f : DefaultFormula n
units : List (Literal (PosFin n))
c : DefaultClause n
h :
  some c ∈ f.clauses.data ∨
    (∃ a,
        (a, false) ∈ (List.foldl insertUnit (f.rupUnits, f.assignments, false) units).fst.data ∧ unit (a, false) = c ∨
          (a, true) ∈ (List.foldl insertUnit (f.rupUnits, f.assignments, false) units).fst.data ∧ unit (a, true) = c) ∨
      ∃ a, (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = c ∨ (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = c
hb : ∀ (l : Literal (PosFin n)), l ∈ (f.rupUnits, f.assignments, false).fst.data → l ∈ f.rupUnits.data ∨ l ∈ units
hl :
  ∀ (acc : Array (Literal (PosFin n)) × Array Assignment × Bool),
    (∀ (l : Literal (PosFin n)), l ∈ acc.fst.data → l ∈ f.rupUnits.data ∨ l ∈ units) →
      ∀ (unit : Literal (PosFin n)),
        unit ∈ units → ∀ (l : Literal (PosFin n)), l ∈ (insertUnit acc unit).fst.data → l ∈ f.rupUnits.data ∨ l ∈ units
⊢ (∃ a, (a, false) ∈ units ∧ Clause.unit (a, false) = c ∨ (a, true) ∈ units ∧ Clause.unit (a, true) = c) ∨
    some c ∈ f.clauses.data ∨
      (∃ a, (a, false) ∈ f.rupUnits.data ∧ unit (a, false) = c ∨ (a, true) ∈ f.rupUnits.data ∧ unit (a, true) = c) ∨
        ∃ a, (a, false) ∈ f.ratUnits.data ∧ unit (a, false) = c ∨ (a, true) ∈ f.ratUnits.data ∧ unit (a, true) = c