English
The coercion of the composition equals the composition of the coercions
Русский
Коэрция композиции равна композиции коэрций
LaTeX
$$$$ \uparrow (\phi_1.comp \phi_2) = (\uparrow \phi_1) \circ (\uparrow \phi_2) $$$$
Lean4
/-- Composition of coalgebra homomorphisms. -/
@[simps!]
def comp (φ₁ : B →ₗc[R] C) (φ₂ : A →ₗc[R] B) : A →ₗc[R] C :=
{ (φ₁ : B →ₗ[R] C) ∘ₗ (φ₂ : A →ₗ[R] B) with
counit_comp := by ext; simp
map_comp_comul := by ext; simp [map_comp] }