Theorems · Theorem · functional analysis

MultilinearMap.norm_image_sub_le_of_bound

∀ {𝕜 : Type u} {ι : Type v} {E : ι → Type wE} {G : Type wG} [inst : NontriviallyNormedField 𝕜]
  [inst_1 : (i : ι) → SeminormedAddCommGroup (E i)] [inst_2 : (i : ι) → NormedSpace 𝕜 (E i)]
  [inst_3 : SeminormedAddCommGroup G] [inst_4 : NormedSpace 𝕜 G] [inst_5 : Fintype ι] (f : MultilinearMap 𝕜 E G)
  {C : ℝ},
  0 ≤ C →
    (∀ (m : (i : ι) → E i), ‖f m‖ ≤ C * ∏ i, ‖m i‖) →
      ∀ (m₁ m₂ : (i : ι) → E i),
        ‖f m₁ - f m₂‖ ≤ C * ↑(Fintype.card ι) * max ‖m₁‖ ‖m₂‖ ^ (Fintype.card ι - 1) * ‖m₁ - m₂‖

If f satisfies a boundedness property around 0, one can deduce a bound on f m₁ - f m₂ using the multilinearity. Here, we give a usable but not very precise version. See norm_image_sub_le_of_bound' for a more precise but less usable version. The bound is ‖f m - f m'‖ ≤ C * card ι * ‖m - m'‖ * (max ‖m‖ ‖m'‖) ^ (card ι - 1).

Defined in

Mathlib.Analysis.Normed.Module.Multilinear.Basic

Cited by

3 results in Mathlib

Foundations

Depth 158 from the axioms · uses propext, Classical.choice, Quot.sound

Assumes

NontriviallyNormedFieldSeminormedAddCommGroupNormedSpaceSeminormedAddCommGroupNormedSpaceFintype