English
The set of polynomial laws M →ₚₗ[R] N carries the structure of an AddCommMonoid under pointwise addition.
Русский
Множество полиномальных законов имеет структуру AddCommMonoid под точечно заданным сложением.
LaTeX
$$$(\operatorname{PolynomialLaw}(R,M,N), +, 0) \text{ is an AddCommMonoid}$.$$
Lean4
instance : AddCommMonoid (M →ₚₗ[R] N)
where
add_assoc f g h := by ext; simp only [add_def, add_assoc]
zero_add f := by ext; simp only [add_def, zero_add, zero_def]
add_zero f := by ext; simp only [add_def, add_zero, zero_def]
nsmul n f := (n : R) • f
nsmul_zero f := by simp only [Nat.cast_zero, zero_smul f]
nsmul_succ n f := by simp only [Nat.cast_add, Nat.cast_one, add_smul, one_smul]
add_comm f g := by ext; simp only [add_def, add_comm]