English
If f and g are equal, algEquivOfEq f g hfg is the identity via algHomOfDvd.
Русский
Если f = g, то эллиптично через algEquivOfEq получается тождественный переход через algHomOfDvd.
LaTeX
$$algEquivOfEq f g hfg = identity via algHomOfDvd$$
Lean4
/-- The canonical algebraic equivalence between `AdjoinRoot p` and `AdjoinRoot g`,
where the two polynomials `f g : R[X]` are associated. -/
noncomputable def algEquivOfAssociated (f g : R[X]) (hfg : Associated f g) : AdjoinRoot f ≃ₐ[R] AdjoinRoot g :=
.ofAlgHom (algHomOfDvd f g hfg.symm.dvd) (algHomOfDvd g f hfg.dvd) (by ext; simp) (by ext; simp)