∀ {R : Type u_1} [inst : CommRing R] (M : Submonoid R) {S : Type u_2} [inst_1 : CommRing S] [inst_2 : Algebra R S]
  [inst_3 : IsLocalization M S] (x : ↥M), ↑((IsLocalization.toInvSubmonoid M S) x) = IsLocalization.mk' S 1 x