fpvandoorn/carleson
Source indexedtheorem · leanprover/lean4:v4.32.0
carleson_hunt'
Carleson.Classical.CarlesonHunt · Carleson/Classical/CarlesonHunt.lean:236 to 254
Mathematical statement
Exact Lean statement
theorem carleson_hunt' {T : ℝ} [hT : Fact (0 < T)] {f : AddCircle T → ℂ} {p : ℝ≥0∞} (hp : 1 < p)
(hf : MemLp f p) :
∀ᵐ x, Tendsto (partialFourierSum' · f x) atTop (𝓝 (f x))Complete declaration
Lean source
Full Lean sourceLean 4
theorem carleson_hunt' {T : ℝ} [hT : Fact (0 < T)] {f : AddCircle T → ℂ} {p : ℝ≥0∞} (hp : 1 < p) (hf : MemLp f p) : ∀ᵐ x, Tendsto (partialFourierSum' · f x) atTop (𝓝 (f x)) := by set g := fun (x : AddCircle (2 * π)) ↦ f (AddCircle.equivAddCircle (2 * π) T two_pi_pos.ne' hT.out.ne' x) have hg : MemLp g p := by unfold g rw [← memLp_haarAddCircle_iff] at * apply hf.comp_measurePreserving AddCircle.measurePreserving_equivAddCircle have h := carleson_hunt_two_pi hp hg rw [AddCircle.volume_eq_smul_haarAddCircle] at * rw [Measure.ae_ennreal_smul_measure_eq (ofReal_ne_zero_iff.mpr two_pi_pos)] at h apply Measure.ae_smul_measure convert AddCircle.measurePreserving_equivAddCircle.quasiMeasurePreserving.ae h using 4 with x N · exact partialFourierSum'_comp_equivAddCircle.symm · unfold g congr exact (AddEquiv.symm_apply_eq (AddCircle.equivAddCircle (2 * π) T (two_pi_pos.ne') (hT.out.ne'))).mp rfl