English
For any algebra equivalence e, the inverse of mapAlgEquiv σ e equals mapAlgEquiv σ e.symm.
Русский
Для любой эквивалентности e, обратное отображение mapAlgEquiv σ e равно mapAlgEquiv σ e.symm.
LaTeX
$$$$ (mapAlgEquiv \\; σ\\; e)^{-1} = mapAlgEquiv \\; σ\\; e^{-1}. $$$$
Lean4
theorem eval₂_pUnitAlgEquiv_symm {f : Polynomial R} {φ : R →+* S} {a : Unit → S} :
((MvPolynomial.pUnitAlgEquiv R).symm f : MvPolynomial Unit R).eval₂ φ a = f.eval₂ φ (a ()) :=
by
simp only [MvPolynomial.pUnitAlgEquiv_symm_apply]
induction f using Polynomial.induction_on' with
| add f g hf hg => simp [hf, hg]
| monomial n r => simp