fpvandoorn/carleson
Source indexedlemma · leanprover/lean4:v4.32.0
MeasureTheory.estimate_eLpNorm_truncCompl
Carleson.ToMathlib.RealInterpolation.Misc · Carleson/ToMathlib/RealInterpolation/Misc.lean:696 to 720
Mathematical statement
Exact Lean statement
lemma estimate_eLpNorm_truncCompl {p q : ℝ≥0∞}
(p_ne_top : p ≠ ⊤) (hpq : q ∈ Ioc 0 p) (hf : AEStronglyMeasurable f μ) (ht : 0 < t) :
eLpNorm (truncCompl f t) q μ ^ q.toReal ≤
(t ^ (q.toReal - p.toReal)) * eLpNorm f p μ ^ p.toRealComplete declaration
Lean source
Full Lean sourceLean 4
lemma estimate_eLpNorm_truncCompl {p q : ℝ≥0∞} (p_ne_top : p ≠ ⊤) (hpq : q ∈ Ioc 0 p) (hf : AEStronglyMeasurable f μ) (ht : 0 < t) : eLpNorm (truncCompl f t) q μ ^ q.toReal ≤ (t ^ (q.toReal - p.toReal)) * eLpNorm f p μ ^ p.toReal := by have q_ne_top: q ≠ ⊤ := ne_top_of_le_ne_top p_ne_top hpq.2 have p_ne_zero : p ≠ 0 := (hpq.1.trans_le hpq.2).ne' apply le_trans (eLpNorm_truncCompl_le hpq.1.ne' (ne_top_of_le_ne_top p_ne_top hpq.2)) calc _ ≤ (t ^ (q.toReal - p.toReal)) * ∫⁻ x : α in {x | t < ‖f x‖ₑ}, ‖f x‖ₑ ^ p.toReal ∂μ := by rw [← lintegral_const_mul'] · apply setLIntegral_mono_ae (AEMeasurable.restrict (by fun_prop)) filter_upwards with x hx rw [mul_comm] exact rpow_le_rpow_of_exponent_le_base_ge_enorm ht hx.ne_top hx.le (toReal_mono p_ne_top hpq.2) · by_cases ht' : t = ⊤ · simp_all · finiteness _ ≤ (t ^ (q.toReal - p.toReal)) * ∫⁻ x : α, ‖f x‖ₑ ^ p.toReal ∂μ := by gcongr exact Measure.restrict_le_self _ = _ := by congr rw [eLpNorm_eq_lintegral_rpow_enorm_toReal p_ne_zero p_ne_top, one_div, ENNReal.rpow_inv_rpow] exact (toReal_pos p_ne_zero p_ne_top).ne'