AlexKontorovich/PrimeNumberTheoremAnd
Source indexedtheorem · leanprover/lean4:v4.32.0
intervalIntegral.interval_add_Ioi
PrimeNumberTheoremAnd.IEANTN.RosserSchoenfeld.RosserSchoenfeldPrime · PrimeNumberTheoremAnd/IEANTN/RosserSchoenfeld/RosserSchoenfeldPrime.lean:615 to 623
Mathematical statement
Exact Lean statement
theorem _root_.intervalIntegral.interval_add_Ioi {E : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E]
{a b : ℝ} {f : ℝ → E} {μ : Measure ℝ} (ha : IntegrableOn f (Set.Ioi a) μ)
(hb : IntegrableOn f (Set.Ioi b) μ) :
∫ (x : ℝ) in a..b, f x ∂μ + ∫ (x : ℝ) in Set.Ioi b, f x ∂μ
= ∫ (x : ℝ) in Set.Ioi a, f x ∂μComplete declaration
Lean source
Full Lean sourceLean 4
theorem _root_.intervalIntegral.interval_add_Ioi {E : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E] {a b : ℝ} {f : ℝ → E} {μ : Measure ℝ} (ha : IntegrableOn f (Set.Ioi a) μ) (hb : IntegrableOn f (Set.Ioi b) μ) : ∫ (x : ℝ) in a..b, f x ∂μ + ∫ (x : ℝ) in Set.Ioi b, f x ∂μ = ∫ (x : ℝ) in Set.Ioi a, f x ∂μ := by wlog hab : a ≤ b generalizing a b · rw [integral_symm, ← this hb ha (le_of_not_ge hab)]; grind rw [integral_of_le hab, ← setIntegral_union Set.Ioc_disjoint_Ioi_same measurableSet_Ioi (ha.mono_set Set.Ioc_subset_Ioi_self) hb, Set.Ioc_union_Ioi_eq_Ioi hab]