English
The action of S on AdjoinRoot f commutes with the embedding of R, i.e., a · of f x = of f (a · x) for a ∈ S and x ∈ R.
Русский
Действие S на AdjoinRoot f commute с вложением R: a · of f x = of f (a · x).
LaTeX
$$$a \\cdot of f x = of f (a \\cdot x)$$$
Lean4
theorem smul_of [DistribSMul S R] [IsScalarTower S R R] (a : S) (x : R) : a • of f x = of f (a • x) := by
rw [of, RingHom.comp_apply, RingHom.comp_apply, smul_mk, smul_C]