∀ {A B : CommRingCat} (f g : A ⟶ B) (s : CategoryTheory.Limits.Fork f g),
  CategoryTheory.CategoryStruct.comp
        (CommRingCat.ofHom
          ((CommRingCat.Hom.hom s.ι).codRestrict ((CommRingCat.Hom.hom f).eqLocus (CommRingCat.Hom.hom g)) ⋯))
        (CommRingCat.equalizerFork f g).ι =
      s.ι ∧
    ∀ {m : s.pt ⟶ (CommRingCat.equalizerFork f g).pt},
      CategoryTheory.CategoryStruct.comp m (CommRingCat.equalizerFork f g).ι = s.ι →
        m =
          CommRingCat.ofHom
            ((CommRingCat.Hom.hom s.ι).codRestrict ((CommRingCat.Hom.hom f).eqLocus (CommRingCat.Hom.hom g)) ⋯)