rw [reduce_fold_fn] at h
case left
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
res : ReduceResult (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) res
h : reduce_fold_fn assignment res c_arr[↑idx] = reducedToEmpty
p : PosFin n → Bool
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)
case left
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
res : ReduceResult (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) res
h :
  (match res with
    | encounteredBoth => encounteredBoth
    | reducedToEmpty =>
      match assignment[c_arr[↑idx].fst.val]! with
      | pos => if c_arr[↑idx].snd = true then reducedToUnit c_arr[↑idx] else reducedToEmpty
      | neg => if (!c_arr[↑idx].snd) = true then reducedToUnit c_arr[↑idx] else reducedToEmpty
      | both => encounteredBoth
      | unassigned => reducedToUnit c_arr[↑idx]
    | reducedToUnit l' =>
      match assignment[c_arr[↑idx].fst.val]! with
      | pos => if c_arr[↑idx].snd = true then reducedToNonunit else reducedToUnit l'
      | neg => if (!c_arr[↑idx].snd) = true then reducedToNonunit else reducedToUnit l'
      | both => encounteredBoth
      | unassigned => reducedToNonunit
    | reducedToNonunit => reducedToNonunit) =
    reducedToEmpty
p : PosFin n → Bool
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)