. refine ⟨f_readyForRupAdd.1, f_readyForRupAdd.2.1, ?_⟩
  intro i b hb
  have hf := f_readyForRupAdd.2.2 i b hb
  simp only [toList, Array.toList_eq, List.append_assoc, List.mem_append, List.mem_filterMap, id_eq, exists_eq_right,
    List.mem_map, Prod.exists, Bool.exists_bool] at hf
  simp only [toList, Array.toList_eq, Array.push_data, List.append_assoc, List.mem_append, List.mem_filterMap,
    List.mem_singleton, id_eq, exists_eq_right, Option.some.injEq, List.mem_map, Prod.exists, Bool.exists_bool]
  rcases hf with hf | hf
  . exact (Or.inl ∘ Or.inl) hf
  . exact Or.inr hf
case h_1
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
heq✝ : c.isUnit = none
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments }.readyForRupAdd

case h_2
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l✝ : PosFin n
heq✝ : c.isUnit = some (l✝, true)
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments.modify l✝.val addPosAssignment }.readyForRupAdd

case h_3
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l✝ : PosFin n
heq✝ : c.isUnit = some (l✝, false)
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments.modify l✝.val addNegAssignment }.readyForRupAdd
case h_2
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l✝ : PosFin n
heq✝ : c.isUnit = some (l✝, true)
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments.modify l✝.val addPosAssignment }.readyForRupAdd

case h_3
n : Nat
f : DefaultFormula n
c : DefaultClause n
f_readyForRupAdd : f.readyForRupAdd
x✝ : Option (Literal (PosFin n))
l✝ : PosFin n
heq✝ : c.isUnit = some (l✝, false)
⊢ { clauses := f.clauses.push (some c), rupUnits := f.rupUnits, ratUnits := f.ratUnits,
      assignments := f.assignments.modify l✝.val addNegAssignment }.readyForRupAdd