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TauCeti.MeasureTheory.Function.Lp.L1Convergence

Lᵖ convergence implies L¹ convergence on a finite measure space #

On a finite measure space the Lᵖ seminorm dominates the L¹ seminorm up to the factor μ(univ)^(1 - 1/p), so a sequence converging in Lᵖ converges in L¹. Stated with the L¹ distance written as a lower Lebesgue integral, which is the form consumed by arguments that pass an integral identity to a limit.

Main declarations #

theorem TauCeti.tendsto_lintegral_enorm_sub_of_tendsto_Lp {α : Type u_1} {G : Type u_2} {ι : Type u_3} [MeasurableSpace α] {ν : MeasureTheory.Measure α} [MeasureTheory.IsFiniteMeasure ν] [NormedAddCommGroup G] [NormedSpace ℝ G] {q : ENNReal} [Fact (1 ≤ q)] {l : Filter ι} {f : ι → ↥(MeasureTheory.Lp G q ν)} {g : ↥(MeasureTheory.Lp G q ν)} (h : Filter.Tendsto f l (nhds g)) :
Filter.Tendsto (fun (i : ι) => ∫⁻ (x : α), ‖↑↑(f i) x - ↑↑g x‖ₑ ∂ν) l (nhds 0)

On a finite measure space, Lᵖ convergence implies L¹ convergence.