∀ {R : Type u_1} [inst : NonAssocRing R] [inst_1 : LinearOrder R] [inst_2 : IsOrderedAddMonoid R]
  [inst_3 : Archimedean R] {p : R} (hp : 0 < p) (a b : R) (m : ℕ), toIcoMod hp (a - ↑m * p) b = toIcoMod hp a b - ↑m * p