Theorem: ENNReal.lintegral_Lp_add_le_of_le_one
File: Mathlib/MeasureTheory/Integral/MeanInequalities.lean

tactic: rcases eq_or_lt_of_le hp0 with (rfl | hp)
state_before: α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
⊢ (∫⁻ (a : α), (f + g) a ^ p ∂μ) ^ (1 / p) ≤
    2 ^ (1 / p - 1) * ((∫⁻ (a : α), f a ^ p ∂μ) ^ (1 / p) + (∫⁻ (a : α), g a ^ p ∂μ) ^ (1 / p))
state_after: case inl
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ 0
hp1 : 0 ≤ 1
⊢ (∫⁻ (a : α), (f + g) a ^ 0 ∂μ) ^ (1 / 0) ≤
    2 ^ (1 / 0 - 1) * ((∫⁻ (a : α), f a ^ 0 ∂μ) ^ (1 / 0) + (∫⁻ (a : α), g a ^ 0 ∂μ) ^ (1 / 0))

case inr
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
⊢ (∫⁻ (a : α), (f + g) a ^ p ∂μ) ^ (1 / p) ≤
    2 ^ (1 / p - 1) * ((∫⁻ (a : α), f a ^ p ∂μ) ^ (1 / p) + (∫⁻ (a : α), g a ^ p ∂μ) ^ (1 / p))

tactic: calc
  (∫⁻ a, (f + g) a ^ p ∂μ) ^ (1 / p) ≤ ((∫⁻ a, f a ^ p ∂μ) + ∫⁻ a, g a ^ p ∂μ) ^ (1 / p) := by
    rw [← lintegral_add_left' (hf.pow_const p)]
    gcongr with a
    exact rpow_add_le_add_rpow _ _ hp0 hp1
  _ ≤ (2 : ℝ≥0∞) ^ (1 / p - 1) * ((∫⁻ a, f a ^ p ∂μ) ^ (1 / p) + (∫⁻ a, g a ^ p ∂μ) ^ (1 / p)) :=
    rpow_add_le_mul_rpow_add_rpow _ _ ((one_le_div hp).2 hp1)
state_before: case inr
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
⊢ (∫⁻ (a : α), (f + g) a ^ p ∂μ) ^ (1 / p) ≤
    2 ^ (1 / p - 1) * ((∫⁻ (a : α), f a ^ p ∂μ) ^ (1 / p) + (∫⁻ (a : α), g a ^ p ∂μ) ^ (1 / p))
state_after: no goals

tactic: simp only [Pi.add_apply, rpow_zero, lintegral_one, _root_.div_zero, zero_sub]
state_before: case inl
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ 0
hp1 : 0 ≤ 1
⊢ (∫⁻ (a : α), (f + g) a ^ 0 ∂μ) ^ (1 / 0) ≤
    2 ^ (1 / 0 - 1) * ((∫⁻ (a : α), f a ^ 0 ∂μ) ^ (1 / 0) + (∫⁻ (a : α), g a ^ 0 ∂μ) ^ (1 / 0))
state_after: case inl
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ 0
hp1 : 0 ≤ 1
⊢ 1 ≤ 2 ^ (-1) * (1 + 1)

tactic: norm_num
state_before: case inl
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ 0
hp1 : 0 ≤ 1
⊢ 1 ≤ 2 ^ (-1) * (1 + 1)
state_after: case inl
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ 0
hp1 : 0 ≤ 1
⊢ 1 ≤ 2 ^ (-1) * 2

tactic: rw [rpow_neg, rpow_one, ENNReal.inv_mul_cancel two_ne_zero two_ne_top]
state_before: case inl
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ 0
hp1 : 0 ≤ 1
⊢ 1 ≤ 2 ^ (-1) * 2
state_after: no goals

tactic: rw [← lintegral_add_left' (hf.pow_const p)]
state_before: α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
⊢ (∫⁻ (a : α), (f + g) a ^ p ∂μ) ^ (1 / p) ≤ (∫⁻ (a : α), f a ^ p ∂μ + ∫⁻ (a : α), g a ^ p ∂μ) ^ (1 / p)
state_after: α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
⊢ (∫⁻ (a : α), (f + g) a ^ p ∂μ) ^ (1 / p) ≤ (∫⁻ (a : α), f a ^ p + g a ^ p ∂μ) ^ (1 / p)

tactic: gcongr with a
state_before: α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
⊢ (∫⁻ (a : α), (f + g) a ^ p ∂μ) ^ (1 / p) ≤ (∫⁻ (a : α), f a ^ p + g a ^ p ∂μ) ^ (1 / p)
state_after: case h₁.hfg
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
a : α
⊢ (f + g) a ^ p ≤ f a ^ p + g a ^ p

tactic: exact rpow_add_le_add_rpow _ _ hp0 hp1
state_before: case h₁.hfg
α : Type u_1
inst✝ : MeasurableSpace α
μ : Measure α
p : ℝ
f g : α → ℝ≥0∞
hf : AEMeasurable f μ
hp0 : 0 ≤ p
hp1 : p ≤ 1
hp : 0 < p
a : α
⊢ (f + g) a ^ p ≤ f a ^ p + g a ^ p
state_after: no goals