English
There is an algebra isomorphism between the quotient by the zero ideal and the base algebra, realized as an AlgEquiv.
Русский
Существует алгебра-физический изоморфизм между частным по нулевому идеалу и базовой алгеброй, реализованный как AlgEquiv.
LaTeX
$$$\\text{AlgEquiv}\\;\\big(R\\,;\\; S\\big) : (S / \\bot) \\cong_{R} S$$$
Lean4
/-- `RingEquiv.quotientBot` as an algebra isomorphism. -/
def quotientBot [CommSemiring R] [Ring S] [Algebra R S] : (S ⧸ (⊥ : Ideal S)) ≃ₐ[R] S
where
__ := RingEquiv.quotientBot S
commutes' x := by simp [← Ideal.Quotient.mk_algebraMap]