English
For a multilinear map f and a tail m, the tail-bound inequality holds: the norm of f applied to tail(m) is bounded by the product with the x-vector tail.
Русский
Для многолинейного отображения f и хвоста m выполняется неравенство: нормa f( tail m ) ограничена произведением и нормой хвоста.
LaTeX
$$$\|f( tail\; m)\| \leq \|f\| \cdot \prod_i \|m_i\|$$$
Lean4
theorem norm_map_init_le (f : ContinuousMultilinearMap 𝕜 (fun i : Fin n => Ei <| castSucc i) (Ei (last n) →L[𝕜] G))
(m : ∀ i, Ei i) : ‖f (init m) (m (last n))‖ ≤ ‖f‖ * ∏ i, ‖m i‖ :=
by
rw [prod_univ_castSucc, ← mul_assoc]
exact (f (init m)).le_of_opNorm_le (f.le_opNorm _) _