English
Let a ∈ AddMonoidAlgebra R Nat. For n ∈ ℕ, the finsupp embedding commutes with exponentiation: (⟨a^n⟩) = ⟨a⟩^n.
Русский
Пусть a ∈ AddMonoidAlgebra R Nat. Для n ∈ ℕ отображение in finsupp сохраняет возведение в степень: (⟨a^n⟩) = ⟨a⟩^n.
LaTeX
$$$\\langle a^n \\rangle = \\langle a \\rangle^n$$$
Lean4
@[simp]
theorem ofFinsupp_pow (a) (n : ℕ) : (⟨a ^ n⟩ : R[X]) = ⟨a⟩ ^ n :=
by
change _ = npowRec n _
induction n with
| zero => simp [npowRec]
| succ n n_ih => simp [npowRec, n_ih, pow_succ]