have l_in_bounds : l.1.1 < assignments.size := by rw [assignments_size]; exact l.1.2.2
n : Nat
assignments : Array Assignment
assignments_size : assignments.size = n
units : Array (Literal (PosFin n))
foundContradiction : Bool
l : Literal (PosFin n)
insertUnit_res : Array (Literal (PosFin n)) × Array Assignment × Bool :=
  insertUnit (units, assignments, foundContradiction) l
h : foundContradiction = true → ∃ i, assignments[i.val] = both
insertUnit_success :
  (if hasAssignment l.snd assignments[l.fst.val]! = true then (units, assignments, foundContradiction)
        else
          (units.push l, assignments.modify l.fst.val (addAssignment l.snd),
            foundContradiction || assignments[l.fst.val]! != unassigned)).snd.snd =
    true
⊢ ∃ j, (insertUnit (units, assignments, foundContradiction) l).snd.fst[j.val] = both
n : Nat
assignments : Array Assignment
assignments_size : assignments.size = n
units : Array (Literal (PosFin n))
foundContradiction : Bool
l : Literal (PosFin n)
insertUnit_res : Array (Literal (PosFin n)) × Array Assignment × Bool :=
  insertUnit (units, assignments, foundContradiction) l
h : foundContradiction = true → ∃ i, assignments[i.val] = both
insertUnit_success :
  (if hasAssignment l.snd assignments[l.fst.val]! = true then (units, assignments, foundContradiction)
        else
          (units.push l, assignments.modify l.fst.val (addAssignment l.snd),
            foundContradiction || assignments[l.fst.val]! != unassigned)).snd.snd =
    true
l_in_bounds : l.fst.val < assignments.size
⊢ ∃ j, (insertUnit (units, assignments, foundContradiction) l).snd.fst[j.val] = both