theorem
lemma43
{α : Type u_1}
[αnonempty : Nonempty α]
[Fintype α]
[AddCommGroup α]
{β : Type u_2}
[Nonempty β]
[Fintype β]
[AddCommGroup β]
(a : α → ℝ)
[DecidableEq β]
(t : NNReal)
(ε : NNReal)
(h : ∀ (χ : AddChar α ℂ), AddChar.IsNontrivial χ → ‖cft (fun (x : α) => ↑(a x)) χ‖ ≤ ↑ε / ↑(Fintype.card α))
(σ : α → β)
(h₂ : ∀ (χ : AddChar β ℂ), ‖cft (⇑χ ∘ σ)‖_[1] ≤ ↑t)
:
‖σ # a - σ # Function.const α (Finset.expect Finset.univ fun (x : α) => a x)‖_[1] ≤ ↑t * ↑ε * √↑(Fintype.card β)
theorem
range_eq_zmod_image
(n : ℕ+)
:
Finset.range ↑n = Finset.image (fun (t : ZMod ↑n) => ZMod.val t) Finset.univ