. split at h <;> contradiction
case h_2
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
p : PosFin n → Bool
acc✝ : ReduceResult (PosFin n)
l : Literal (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) (reducedToUnit l)
x✝ : Assignment
heq✝ : assignment[c_arr[↑idx].fst.val]! = neg
h : (if (!c_arr[↑idx].snd) = true then reducedToNonunit else reducedToUnit l) = reducedToEmpty
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)

case h_3
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
p : PosFin n → Bool
acc✝ : ReduceResult (PosFin n)
l : Literal (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) (reducedToUnit l)
x✝ : Assignment
heq✝ : assignment[c_arr[↑idx].fst.val]! = both
h : encounteredBoth = reducedToEmpty
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)

case h_4
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
p : PosFin n → Bool
acc✝ : ReduceResult (PosFin n)
l : Literal (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) (reducedToUnit l)
x✝ : Assignment
heq✝ : assignment[c_arr[↑idx].fst.val]! = unassigned
h : reducedToNonunit = reducedToEmpty
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)
case h_3
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
p : PosFin n → Bool
acc✝ : ReduceResult (PosFin n)
l : Literal (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) (reducedToUnit l)
x✝ : Assignment
heq✝ : assignment[c_arr[↑idx].fst.val]! = both
h : encounteredBoth = reducedToEmpty
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)

case h_4
n : Nat
c_arr : Array (Literal (PosFin n))
assignment : Array Assignment
idx : Fin c_arr.size
p : PosFin n → Bool
acc✝ : ReduceResult (PosFin n)
l : Literal (PosFin n)
ih : reduce_postcondition_induction_motive c_arr assignment (↑idx) (reducedToUnit l)
x✝ : Assignment
heq✝ : assignment[c_arr[↑idx].fst.val]! = unassigned
h : reducedToNonunit = reducedToEmpty
⊢ (∀ (i : Fin c_arr.size), ↑i < ↑idx + 1 → ¬(p ⊨ c_arr[↑i])) ∨ ¬(p ⊨ assignment)