(∀ {b : Bool} {l : List Bool},
    List.IsChain (fun x1 x2 => x1 ≠ x2) (b :: l) → List.count (!b) l = List.count b l + l.length % 2) →
  ∀ (b x : Bool) (l : List Bool),
    List.IsChain (fun x1 x2 => x1 ≠ x2) (b :: x :: l) →
      List.count (!b) (x :: l) = List.count b (x :: l) + (x :: l).length % 2