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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.toReal

Complete declaration

Lean source

Canonical source
Full Lean sourceLean 4
lemma estimate_eLpNorm_truncCompl {p q : 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'