. apply Or.inr ∘ Or.inl
  have j_lt_derivedLits_arr_size : j.1 < derivedLits_arr.size := by
    simp only [derivedLits_arr_def, Array.size_mk]
    exact j.2
  have i_gt_zero : i.1 > 0 := by rw [← j_eq_i]; exact (List.get derivedLits j).1.2.1
  refine ⟨⟨j.1, j_lt_derivedLits_arr_size⟩, List.get derivedLits j |>.2, i_gt_zero, ?_⟩
  constructor
  . apply Nat.zero_le
  . constructor
    . simp only [derivedLits_arr_def, Fin.getElem_fin, Array.getElem_eq_data_get, ← j_eq_i]
      rfl
    . apply And.intro h1 ∘ And.intro h2
      intro k _ k_ne_j
      have k_in_bounds : k < derivedLits.length := by
        have k_property := k.2
        simp only [derivedLits_arr_def, Array.size_mk] at k_property
        exact k_property
      have k_ne_j : ⟨k.1, k_in_bounds⟩ ≠ j := by
        apply Fin.ne_of_val_ne
        simp only
        exact Fin.val_ne_of_ne k_ne_j
      simp only [Fin.getElem_fin, Array.getElem_eq_data_get, ne_eq, derivedLits_arr_def]
      exact h3 ⟨k.1, k_in_bounds⟩ k_ne_j
case inr.inl.intro.intro.intro.intro
rupHints : Array Nat
n : Nat
f : DefaultFormula n
f_assignments_size : f.assignments.size = n
f' : DefaultFormula n
_f'_def : f' = (f.performRupCheck rupHints).fst
f'_assignments_size : f'.assignments.size = n
derivedLits : List (Literal (PosFin n))
derivedLits_arr : Array (Literal (PosFin n))
derivedLits_arr_def : derivedLits_arr = { data := derivedLits }
_derivedLits_arr_nodup : ∀ (i j : Fin derivedLits_arr.size), i ≠ j → derivedLits_arr[i] ≠ derivedLits_arr[j]
i : Fin n
j : Fin derivedLits.length
j_eq_i : (derivedLits.get j).fst.val = ↑i
h1 : f'.assignments[↑i] = addAssignment (derivedLits.get j).snd f.assignments[↑i]
h2 : ¬hasAssignment (derivedLits.get j).snd f.assignments[↑i] = true
h3 : ∀ (k : Fin derivedLits.length), k ≠ j → (derivedLits.get k).fst.val ≠ ↑i
⊢ let_fun i_lt_assignments_size := ⋯;
  let_fun i_lt_f_assignments_size := ⋯;
  let assignments_i := f'.assignments[↑i];
  let fassignments_i := f.assignments[↑i];
  (assignments_i = fassignments_i ∧ ∀ (j : Fin derivedLits_arr.size), ↑j ≥ 0 → derivedLits_arr[j].fst.val ≠ ↑i) ∨
    (∃ j b i_gt_zero,
        ↑j ≥ 0 ∧
          derivedLits_arr[j] = (⟨↑i, ⋯⟩, b) ∧
            assignments_i = addAssignment b fassignments_i ∧
              ¬hasAssignment b fassignments_i = true ∧
                ∀ (k : Fin derivedLits_arr.size), ↑k ≥ 0 → k ≠ j → derivedLits_arr[k].fst.val ≠ ↑i) ∨
      ∃ j1 j2 i_gt_zero,
        ↑j1 ≥ 0 ∧
          ↑j2 ≥ 0 ∧
            derivedLits_arr[j1] = (⟨↑i, ⋯⟩, true) ∧
              derivedLits_arr[j2] = (⟨↑i, ⋯⟩, false) ∧
                assignments_i = both ∧
                  fassignments_i = unassigned ∧
                    ∀ (k : Fin derivedLits_arr.size), ↑k ≥ 0 → k ≠ j1 → k ≠ j2 → derivedLits_arr[k].fst.val ≠ ↑i

case inr.inr.intro.intro.intro.intro.intro.intro.intro.intro
rupHints : Array Nat
n : Nat
f : DefaultFormula n
f_assignments_size : f.assignments.size = n
f' : DefaultFormula n
_f'_def : f' = (f.performRupCheck rupHints).fst
f'_assignments_size : f'.assignments.size = n
derivedLits : List (Literal (PosFin n))
derivedLits_arr : Array (Literal (PosFin n))
derivedLits_arr_def : derivedLits_arr = { data := derivedLits }
_derivedLits_arr_nodup : ∀ (i j : Fin derivedLits_arr.size), i ≠ j → derivedLits_arr[i] ≠ derivedLits_arr[j]
i : Fin n
j1 j2 : Fin derivedLits.length
j1_eq_i : (derivedLits.get j1).fst.val = ↑i
j2_eq_i : (derivedLits.get j2).fst.val = ↑i
j1_eq_true : (derivedLits.get j1).snd = true
j2_eq_false : (derivedLits.get j2).snd = false
h1 : f'.assignments[↑i] = both
h2 : f.assignments[↑i] = unassigned
h3 : ∀ (k : Fin derivedLits.length), k ≠ j1 → k ≠ j2 → (derivedLits.get k).fst.val ≠ ↑i
⊢ let_fun i_lt_assignments_size := ⋯;
  let_fun i_lt_f_assignments_size := ⋯;
  let assignments_i := f'.assignments[↑i];
  let fassignments_i := f.assignments[↑i];
  (assignments_i = fassignments_i ∧ ∀ (j : Fin derivedLits_arr.size), ↑j ≥ 0 → derivedLits_arr[j].fst.val ≠ ↑i) ∨
    (∃ j b i_gt_zero,
        ↑j ≥ 0 ∧
          derivedLits_arr[j] = (⟨↑i, ⋯⟩, b) ∧
            assignments_i = addAssignment b fassignments_i ∧
              ¬hasAssignment b fassignments_i = true ∧
                ∀ (k : Fin derivedLits_arr.size), ↑k ≥ 0 → k ≠ j → derivedLits_arr[k].fst.val ≠ ↑i) ∨
      ∃ j1 j2 i_gt_zero,
        ↑j1 ≥ 0 ∧
          ↑j2 ≥ 0 ∧
            derivedLits_arr[j1] = (⟨↑i, ⋯⟩, true) ∧
              derivedLits_arr[j2] = (⟨↑i, ⋯⟩, false) ∧
                assignments_i = both ∧
                  fassignments_i = unassigned ∧
                    ∀ (k : Fin derivedLits_arr.size), ↑k ≥ 0 → k ≠ j1 → k ≠ j2 → derivedLits_arr[k].fst.val ≠ ↑i
case inr.inr.intro.intro.intro.intro.intro.intro.intro.intro
rupHints : Array Nat
n : Nat
f : DefaultFormula n
f_assignments_size : f.assignments.size = n
f' : DefaultFormula n
_f'_def : f' = (f.performRupCheck rupHints).fst
f'_assignments_size : f'.assignments.size = n
derivedLits : List (Literal (PosFin n))
derivedLits_arr : Array (Literal (PosFin n))
derivedLits_arr_def : derivedLits_arr = { data := derivedLits }
_derivedLits_arr_nodup : ∀ (i j : Fin derivedLits_arr.size), i ≠ j → derivedLits_arr[i] ≠ derivedLits_arr[j]
i : Fin n
j1 j2 : Fin derivedLits.length
j1_eq_i : (derivedLits.get j1).fst.val = ↑i
j2_eq_i : (derivedLits.get j2).fst.val = ↑i
j1_eq_true : (derivedLits.get j1).snd = true
j2_eq_false : (derivedLits.get j2).snd = false
h1 : f'.assignments[↑i] = both
h2 : f.assignments[↑i] = unassigned
h3 : ∀ (k : Fin derivedLits.length), k ≠ j1 → k ≠ j2 → (derivedLits.get k).fst.val ≠ ↑i
⊢ let_fun i_lt_assignments_size := ⋯;
  let_fun i_lt_f_assignments_size := ⋯;
  let assignments_i := f'.assignments[↑i];
  let fassignments_i := f.assignments[↑i];
  (assignments_i = fassignments_i ∧ ∀ (j : Fin derivedLits_arr.size), ↑j ≥ 0 → derivedLits_arr[j].fst.val ≠ ↑i) ∨
    (∃ j b i_gt_zero,
        ↑j ≥ 0 ∧
          derivedLits_arr[j] = (⟨↑i, ⋯⟩, b) ∧
            assignments_i = addAssignment b fassignments_i ∧
              ¬hasAssignment b fassignments_i = true ∧
                ∀ (k : Fin derivedLits_arr.size), ↑k ≥ 0 → k ≠ j → derivedLits_arr[k].fst.val ≠ ↑i) ∨
      ∃ j1 j2 i_gt_zero,
        ↑j1 ≥ 0 ∧
          ↑j2 ≥ 0 ∧
            derivedLits_arr[j1] = (⟨↑i, ⋯⟩, true) ∧
              derivedLits_arr[j2] = (⟨↑i, ⋯⟩, false) ∧
                assignments_i = both ∧
                  fassignments_i = unassigned ∧
                    ∀ (k : Fin derivedLits_arr.size), ↑k ≥ 0 → k ≠ j1 → k ≠ j2 → derivedLits_arr[k].fst.val ≠ ↑i