English
In the zero-index case, the norm of mkPiAlgebraFin is exactly the norm of 1 in A, preserving the normalization of the construction in the empty product.
Русский
В нульовом случае норма mkPiAlgebraFin точна равна норме единицы в A, сохраняющей нормировку конструкции в пустом произведении.
LaTeX
$$$\|\mathrm{mkPiAlgebraFin}_{\mathbb{K}}(0, A)\| = \|1\|$$$
Lean4
@[simp]
theorem norm_mkPiAlgebraFin [NormOneClass A] : ‖ContinuousMultilinearMap.mkPiAlgebraFin 𝕜 n A‖ = 1 :=
by
cases n
· rw [norm_mkPiAlgebraFin_zero]
simp
· refine le_antisymm norm_mkPiAlgebraFin_succ_le ?_
refine le_of_eq_of_le ?_ <| ratio_le_opNorm (ContinuousMultilinearMap.mkPiAlgebraFin 𝕜 (Nat.succ _) A) fun _ => 1
simp