English
The unit composed with antipode yields the unit: η[A] ≫ 𝒮[A] = η[A].
Русский
Единица композиции с antipode дает единицу: η[A] ≫ 𝒮[A] = η[A].
LaTeX
$$$ η[A] \circ 𝒮[A] = η[A] $$$
Lean4
@[reassoc (attr := simp)]
theorem one_antipode (A : C) [HopfObj A] : η[A] ≫ 𝒮[A] = η[A] :=
by
have := (rfl : η[A] ≫ Δ[A] ≫ (𝒮[A] ▷ A) ≫ μ[A] = _)
conv at this =>
rhs
rw [antipode_left]
rw [Bimon.one_comul_assoc, tensorHom_def_assoc, unitors_inv_equal, ← rightUnitor_inv_naturality_assoc,
whisker_exchange_assoc, ← rightUnitor_inv_naturality_assoc, rightUnitor_inv_naturality_assoc] at this
simpa