English
The optionEquivRight is the isomorphism described between polynomials with option-indexed variables and polynomials with polynomial coefficients.
Русский
optionEquivRight есть указанное изоморфизм между полиномами с опциональными индексами переменных и полиномами со степенью коэффициентов полиномов.
LaTeX
$$$\\text{def }\\operatorname{finSuccEquiv} : \\ldots$$$
Lean4
/-- The algebra isomorphism between multivariable polynomials in `Fin (n + 1)` and
polynomials over multivariable polynomials in `Fin n`.
-/
def finSuccEquiv : MvPolynomial (Fin (n + 1)) R ≃ₐ[R] Polynomial (MvPolynomial (Fin n) R) :=
(renameEquiv R (_root_.finSuccEquiv n)).trans (optionEquivLeft R (Fin n))