English
The surjectivity of mkAlgHom S s holds: every element of RingQuot s is the image of some element of A under mkAlgHom.
Русский
Сюръективность mkAlgHom S s (повтор): каждый элемент RingQuot s является образом некоторого элемента A.
LaTeX
$$∀ y:\\, RingQuot s, ∃ a:\\, A, mkAlgHom S s a = y$$
Lean4
theorem mkAlgHom_surjective (s : A → A → Prop) : Function.Surjective (mkAlgHom S s) :=
by
suffices Function.Surjective fun x ↦ (⟨.mk (Rel s) x⟩ : RingQuot s) by simpa [mkAlgHom_def, mkRingHom_def]
rintro ⟨⟨a⟩⟩
use a