English
The bilinear structure llcomp describes how to pair a linear map with a derivation to obtain a new derivation, respecting addition and scalar multiplication.
Русский
В двоичной структуре llcomp линейное отображение и деривация образуют новую деривацию, сохраняющую сложение и умножение на скаляры.
LaTeX
$$$\text{llcomp} : (M \to_A N) \to Derivation(R,A,M) \to Derivation(R,A,N)$ is linear in both arguments.$$
Lean4
/-- The composition of a derivation with a linear map as a bilinear map -/
@[simps]
def llcomp : (M →ₗ[A] N) →ₗ[A] Derivation R A M →ₗ[R] Derivation R A N
where
toFun f := f.compDer
map_add' f₁ f₂ := by ext; rfl
map_smul' r D := by ext; rfl