chore: remove parentheses in interval integral notation (#29017)

This is possible since leanprover/lean4#8784

Co-authored-by: Floris van Doorn <[email protected]>

Author: fpvandoorn

Archive/Wiedijk100Theorems/BuffonsNeedle.lean

@@ -279,11 +279,11 @@ lemma intervalIntegrable_min_const_sin_mul (a b : ℝ) :
 
 /--
 This equality is useful since `θ.sin` is increasing in `0..π / 2` (but not in `0..π`).
-Then, `∫ θ in (0)..π / 2, min d (θ.sin * l)` can be split into two adjacent integrals, at the
+Then, `∫ θ in 0..π / 2, min d (θ.sin * l)` can be split into two adjacent integrals, at the
 point where `d = θ.sin * l`, which is `θ = (d / l).arcsin`.
 -/
 lemma integral_min_eq_two_mul :
-    ∫ θ in (0)..π, min d (θ.sin * l) = 2 * ∫ θ in (0)..π / 2, min d (θ.sin * l) := by
+    ∫ θ in 0..π, min d (θ.sin * l) = 2 * ∫ θ in 0..π / 2, min d (θ.sin * l) := by
   rw [← intervalIntegral.integral_add_adjacent_intervals (b := π / 2) (c := π)]
   conv => lhs; arg 2; arg 1; intro θ; rw [← neg_neg θ, Real.sin_neg]
   · simp_rw [intervalIntegral.integral_comp_neg fun θ => min d (-θ.sin * l), ← Real.sin_add_pi,
@@ -293,11 +293,11 @@ lemma integral_min_eq_two_mul :
 
 include hd hl in
 /--
-The first of two adjacent integrals in the long case. In the range `(0)..(d / l).arcsin`, we
-have that `θ.sin * l ≤ d`, and thus the integral is `∫ θ in (0)..(d / l).arcsin, θ.sin * l`.
+The first of two adjacent integrals in the long case. In the range `0..(d / l).arcsin`, we
+have that `θ.sin * l ≤ d`, and thus the integral is `∫ θ in 0..(d / l).arcsin, θ.sin * l`.
 -/
 lemma integral_zero_to_arcsin_min :
-    ∫ θ in (0)..(d / l).arcsin, min d (θ.sin * l) = (1 - √(1 - (d / l) ^ 2)) * l := by
+    ∫ θ in 0..(d / l).arcsin, min d (θ.sin * l) = (1 - √(1 - (d / l) ^ 2)) * l := by
   have : Set.EqOn (fun θ => min d (θ.sin * l)) (Real.sin · * l) (Set.uIcc 0 (d / l).arcsin) := by
     intro θ ⟨hθ₁, hθ₂⟩
     have : 0 ≤ (d / l).arcsin := Real.arcsin_nonneg.mpr (div_nonneg hd.le hl.le)

Mathlib/Analysis/Complex/CauchyIntegral.lean

@@ -297,8 +297,8 @@ theorem circleIntegral_sub_center_inv_smul_eq_of_differentiable_on_annulus_off_c
   rw [Real.exp_le_exp] at hle
   -- Unfold definition of `circleIntegral` and cancel some terms.
   suffices
-    (∫ θ in (0)..2 * π, I • f (circleMap c (Real.exp b) θ)) =
-      ∫ θ in (0)..2 * π, I • f (circleMap c (Real.exp a) θ) by
+    (∫ θ in 0..2 * π, I • f (circleMap c (Real.exp b) θ)) =
+      ∫ θ in 0..2 * π, I • f (circleMap c (Real.exp a) θ) by
     simpa only [circleIntegral, add_sub_cancel_left, ofReal_exp, ← exp_add, smul_smul, ←
       div_eq_mul_inv, mul_div_cancel_left₀ _ (circleMap_ne_center (Real.exp_pos _).ne'),
       circleMap_sub_center, deriv_circleMap]

Mathlib/Analysis/Convolution.lean

@@ -1336,7 +1336,7 @@ bilinear map `L` and measure `ν`. It is defined to be the function mapping `x`
 `∫ t in 0..x, L (f t) (g (x - t)) ∂ν` if `0 < x`, and 0 otherwise. -/
 noncomputable def posConvolution (f : ℝ → E) (g : ℝ → E') (L : E →L[ℝ] E' →L[ℝ] F)
     (ν : Measure ℝ := by volume_tac) : ℝ → F :=
-  indicator (Ioi (0 : ℝ)) fun x => ∫ t in (0)..x, L (f t) (g (x - t)) ∂ν
+  indicator (Ioi (0 : ℝ)) fun x => ∫ t in 0..x, L (f t) (g (x - t)) ∂ν
 
 theorem posConvolution_eq_convolution_indicator (f : ℝ → E) (g : ℝ → E') (L : E →L[ℝ] E' →L[ℝ] F)
     (ν : Measure ℝ := by volume_tac) [NoAtoms ν] :
@@ -1382,7 +1382,7 @@ theorem integral_posConvolution [CompleteSpace E] [CompleteSpace E'] [CompleteSp
     {μ ν : Measure ℝ}
     [SFinite μ] [SFinite ν] [IsAddRightInvariant μ] [NoAtoms ν] {f : ℝ → E} {g : ℝ → E'}
     (hf : IntegrableOn f (Ioi 0) ν) (hg : IntegrableOn g (Ioi 0) μ) (L : E →L[ℝ] E' →L[ℝ] F) :
-    ∫ x : ℝ in Ioi 0, ∫ t : ℝ in (0)..x, L (f t) (g (x - t)) ∂ν ∂μ =
+    ∫ x : ℝ in Ioi 0, ∫ t : ℝ in 0..x, L (f t) (g (x - t)) ∂ν ∂μ =
       L (∫ x : ℝ in Ioi 0, f x ∂ν) (∫ x : ℝ in Ioi 0, g x ∂μ) := by
   rw [← integrable_indicator_iff measurableSet_Ioi] at hf hg
   simp_rw [← integral_indicator measurableSet_Ioi]

Mathlib/Analysis/Real/Pi/Wallis.lean

@@ -67,7 +67,7 @@ theorem W_eq_factorial_ratio (n : ℕ) :
     ring_nf
 
 theorem W_eq_integral_sin_pow_div_integral_sin_pow (k : ℕ) : (π / 2)⁻¹ * W k =
-    (∫ x : ℝ in (0)..π, sin x ^ (2 * k + 1)) / ∫ x : ℝ in (0)..π, sin x ^ (2 * k) := by
+    (∫ x : ℝ in 0..π, sin x ^ (2 * k + 1)) / ∫ x : ℝ in 0..π, sin x ^ (2 * k) := by
   rw [integral_sin_pow_even, integral_sin_pow_odd, mul_div_mul_comm, ← prod_div_distrib, inv_div]
   simp_rw [div_div_div_comm, div_div_eq_mul_div, mul_div_assoc]
   rfl

Mathlib/Analysis/SpecialFunctions/Gamma/Basic.lean

@@ -145,7 +145,7 @@ section GammaRecurrence
 
 /-- The indefinite version of the `Γ` function, `Γ(s, X) = ∫ x ∈ 0..X, exp(-x) x ^ (s - 1)`. -/
 def partialGamma (s : ℂ) (X : ℝ) : ℂ :=
-  ∫ x in (0)..X, (-x).exp * x ^ (s - 1)
+  ∫ x in 0..X, (-x).exp * x ^ (s - 1)
 
 theorem tendsto_partialGamma {s : ℂ} (hs : 0 < s.re) :
     Tendsto (fun X : ℝ => partialGamma s X) atTop (𝓝 <| GammaIntegral s) :=

Mathlib/Analysis/SpecialFunctions/Gamma/Beta.lean

@@ -54,7 +54,7 @@ namespace Complex
 
 /-- The Beta function `Β (u, v)`, defined as `∫ x:ℝ in 0..1, x ^ (u - 1) * (1 - x) ^ (v - 1)`. -/
 noncomputable def betaIntegral (u v : ℂ) : ℂ :=
-  ∫ x : ℝ in (0)..1, (x : ℂ) ^ (u - 1) * (1 - (x : ℂ)) ^ (v - 1)
+  ∫ x : ℝ in 0..1, (x : ℂ) ^ (u - 1) * (1 - (x : ℂ)) ^ (v - 1)
 
 /-- Auxiliary lemma for `betaIntegral_convergent`, showing convergence at the left endpoint. -/
 theorem betaIntegral_convergent_left {u : ℂ} (hu : 0 < re u) (v : ℂ) :
@@ -105,7 +105,7 @@ theorem betaIntegral_eval_one_right {u : ℂ} (hu : 0 < re u) : betaIntegral u 1
   · rwa [sub_re, one_re, ← sub_pos, sub_neg_eq_add, sub_add_cancel]
 
 theorem betaIntegral_scaled (s t : ℂ) {a : ℝ} (ha : 0 < a) :
-    ∫ x in (0)..a, (x : ℂ) ^ (s - 1) * ((a : ℂ) - x) ^ (t - 1) =
+    ∫ x in 0..a, (x : ℂ) ^ (s - 1) * ((a : ℂ) - x) ^ (t - 1) =
     (a : ℂ) ^ (s + t - 1) * betaIntegral s t := by
   have ha' : (a : ℂ) ≠ 0 := ofReal_ne_zero.mpr ha.ne'
   rw [betaIntegral]
@@ -250,7 +250,7 @@ theorem GammaSeq_add_one_left (s : ℂ) {n : ℕ} (hn : n ≠ 0) :
   · abel
 
 theorem GammaSeq_eq_approx_Gamma_integral {s : ℂ} (hs : 0 < re s) {n : ℕ} (hn : n ≠ 0) :
-    GammaSeq s n = ∫ x : ℝ in (0)..n, ↑((1 - x / n) ^ n) * (x : ℂ) ^ (s - 1) := by
+    GammaSeq s n = ∫ x : ℝ in 0..n, ↑((1 - x / n) ^ n) * (x : ℂ) ^ (s - 1) := by
   have : ∀ x : ℝ, x = x / n * n := by intro x; rw [div_mul_cancel₀]; exact Nat.cast_ne_zero.mpr hn
   conv_rhs => enter [1, x, 2, 1]; rw [this x]
   rw [GammaSeq_eq_betaIntegral_of_re_pos hs]
@@ -275,7 +275,7 @@ theorem GammaSeq_eq_approx_Gamma_integral {s : ℂ} (hs : 0 < re s) {n : ℕ} (h
 /-- The main technical lemma for `GammaSeq_tendsto_Gamma`, expressing the integral defining the
 Gamma function for `0 < re s` as the limit of a sequence of integrals over finite intervals. -/
 theorem approx_Gamma_integral_tendsto_Gamma_integral {s : ℂ} (hs : 0 < re s) :
-    Tendsto (fun n : ℕ => ∫ x : ℝ in (0)..n, ((1 - x / n) ^ n : ℝ) * (x : ℂ) ^ (s - 1)) atTop
+    Tendsto (fun n : ℕ => ∫ x : ℝ in 0..n, ((1 - x / n) ^ n : ℝ) * (x : ℂ) ^ (s - 1)) atTop
       (𝓝 <| Gamma s) := by
   rw [Gamma_eq_integral hs]
   -- We apply dominated convergence to the following function, which we will show is uniformly

Mathlib/Analysis/SpecialFunctions/Integrals/Basic.lean

@@ -123,7 +123,7 @@ theorem integral_cpow {r : ℂ} (h : -1 < r.re ∨ r ≠ -1 ∧ (0 : ℝ) ∉ [[
     refine hasDerivAt_ofReal_cpow_const' (ne_of_mem_of_not_mem hx hab) ?_
     contrapose! hr; rwa [add_eq_zero_iff_eq_neg]
   replace h : -1 < r.re := by tauto
-  suffices ∀ c : ℝ, (∫ x : ℝ in (0)..c, (x : ℂ) ^ r) =
+  suffices ∀ c : ℝ, (∫ x : ℝ in 0..c, (x : ℂ) ^ r) =
       (c : ℂ) ^ (r + 1) / (r + 1) - (0 : ℂ) ^ (r + 1) / (r + 1) by
     rw [← integral_add_adjacent_intervals (@intervalIntegrable_cpow' a 0 r h)
       (@intervalIntegrable_cpow' 0 b r h), integral_symm, this a, this b, Complex.zero_cpow hr]
@@ -175,7 +175,7 @@ theorem integral_pow_abs_sub_uIoc : ∫ x in Ι a b, |x - a| ^ n = |b - a| ^ (n
   · calc
       ∫ x in Ι a b, |x - a| ^ n = ∫ x in a..b, |x - a| ^ n := by
         rw [uIoc_of_le hab, ← integral_of_le hab]
-      _ = ∫ x in (0)..(b - a), x ^ n := by
+      _ = ∫ x in 0..(b - a), x ^ n := by
         simp only [integral_comp_sub_right fun x => |x| ^ n, sub_self]
         refine integral_congr fun x hx => congr_arg₂ Pow.pow (abs_of_nonneg <| ?_) rfl
         rw [uIcc_of_le (sub_nonneg.2 hab)] at hx
@@ -271,7 +271,7 @@ lemma integral_exp_mul_I_eq_sinc (r : ℝ) :
   ring
 
 /-- Helper lemma for `integral_log`: case where `a = 0` and `b` is positive. -/
-lemma integral_log_from_zero_of_pos (ht : 0 < b) : ∫ s in (0)..b, log s = b * log b - b := by
+lemma integral_log_from_zero_of_pos (ht : 0 < b) : ∫ s in 0..b, log s = b * log b - b := by
   -- Compute the integral by giving a primitive and considering it limit as x approaches 0 from the
   -- right. The following lines were suggested by Gareth Ma on Zulip.
   rw [integral_eq_sub_of_hasDerivAt_of_tendsto (f := fun x ↦ x * log x - x)
@@ -285,7 +285,7 @@ lemma integral_log_from_zero_of_pos (ht : 0 < b) : ∫ s in (0)..b, log s = b *
   · exact tendsto_nhdsWithin_of_tendsto_nhds (ContinuousAt.tendsto (by fun_prop))
 
 /-- Helper lemma for `integral_log`: case where `a = 0`. -/
-lemma integral_log_from_zero {b : ℝ} : ∫ s in (0)..b, log s = b * log b - b := by
+lemma integral_log_from_zero {b : ℝ} : ∫ s in 0..b, log s = b * log b - b := by
   rcases lt_trichotomy b 0 with h | h | h
   · -- If t is negative, use that log is an even function to reduce to the positive case.
     conv => arg 1; arg 1; intro t; rw [← log_neg_eq_log]
@@ -444,31 +444,31 @@ theorem integral_sin_sq : ∫ x in a..b, sin x ^ 2 = (sin a * cos a - sin b * co
   field_simp [integral_sin_pow, add_sub_assoc]
 
 theorem integral_sin_pow_odd :
-    (∫ x in (0)..π, sin x ^ (2 * n + 1)) = 2 * ∏ i ∈ range n, (2 * (i : ℝ) + 2) / (2 * i + 3) := by
+    (∫ x in 0..π, sin x ^ (2 * n + 1)) = 2 * ∏ i ∈ range n, (2 * (i : ℝ) + 2) / (2 * i + 3) := by
   induction' n with k ih; · norm_num
   rw [prod_range_succ_comm, mul_left_comm, ← ih, mul_succ, integral_sin_pow]
   norm_cast
   simp [-cast_add, field_simps]
 
 theorem integral_sin_pow_even :
-    (∫ x in (0)..π, sin x ^ (2 * n)) = π * ∏ i ∈ range n, (2 * (i : ℝ) + 1) / (2 * i + 2) := by
+    (∫ x in 0..π, sin x ^ (2 * n)) = π * ∏ i ∈ range n, (2 * (i : ℝ) + 1) / (2 * i + 2) := by
   induction' n with k ih; · simp
   rw [prod_range_succ_comm, mul_left_comm, ← ih, mul_succ, integral_sin_pow]
   norm_cast
   simp [-cast_add, field_simps]
 
-theorem integral_sin_pow_pos : 0 < ∫ x in (0)..π, sin x ^ n := by
+theorem integral_sin_pow_pos : 0 < ∫ x in 0..π, sin x ^ n := by
   rcases even_or_odd' n with ⟨k, rfl | rfl⟩ <;>
   simp only [integral_sin_pow_even, integral_sin_pow_odd] <;>
   refine mul_pos (by simp [pi_pos]) (prod_pos fun n _ => div_pos ?_ ?_) <;>
   norm_cast <;>
   omega
 
-theorem integral_sin_pow_succ_le : (∫ x in (0)..π, sin x ^ (n + 1)) ≤ ∫ x in (0)..π, sin x ^ n := by
+theorem integral_sin_pow_succ_le : (∫ x in 0..π, sin x ^ (n + 1)) ≤ ∫ x in 0..π, sin x ^ n := by
   let H x h := pow_le_pow_of_le_one (sin_nonneg_of_mem_Icc h) (sin_le_one x) (n.le_add_right 1)
   refine integral_mono_on pi_pos.le ?_ ?_ H <;> exact (continuous_sin.pow _).intervalIntegrable 0 π
 
-theorem integral_sin_pow_antitone : Antitone fun n : ℕ => ∫ x in (0)..π, sin x ^ n :=
+theorem integral_sin_pow_antitone : Antitone fun n : ℕ => ∫ x in 0..π, sin x ^ n :=
   antitone_nat_of_succ_le integral_sin_pow_succ_le
 
 /-! ### Integral of `cos x ^ n` -/

Mathlib/Analysis/SpecialFunctions/Integrals/LogTrigonometric.lean

@@ -19,7 +19,7 @@ Helper lemma for `integral_log_sin_zero_pi_div_two`: The integral of `log ∘ si
 double the integral on `0 … π/2`.
 -/
 private lemma integral_log_sin_zero_pi_eq_two_mul_integral_log_sin_zero_pi_div_two :
-    ∫ x in (0)..π, log (sin x) = 2 * ∫ x in (0)..(π / 2), log (sin x) := by
+    ∫ x in 0..π, log (sin x) = 2 * ∫ x in 0..(π / 2), log (sin x) := by
   rw [← intervalIntegral.integral_add_adjacent_intervals (a := 0) (b := π / 2) (c := π)
     (by apply intervalIntegrable_log_sin) (by apply intervalIntegrable_log_sin)]
   conv =>
@@ -33,9 +33,9 @@ private lemma integral_log_sin_zero_pi_eq_two_mul_integral_log_sin_zero_pi_div_t
 /--
 The integral of `log ∘ sin` on `0 … π/2` equals `-log 2 * π / 2`.
 -/
-theorem integral_log_sin_zero_pi_div_two : ∫ x in (0)..(π / 2), log (sin x) = -log 2 * π / 2 := by
-  calc ∫ x in (0)..(π / 2), log (sin x)
-    _ = ∫ x in (0)..(π / 2), (log (sin (2 * x)) - log 2 - log (cos x)) := by
+theorem integral_log_sin_zero_pi_div_two : ∫ x in 0..(π / 2), log (sin x) = -log 2 * π / 2 := by
+  calc ∫ x in 0..(π / 2), log (sin x)
+    _ = ∫ x in 0..(π / 2), (log (sin (2 * x)) - log 2 - log (cos x)) := by
       apply intervalIntegral.integral_congr_codiscreteWithin
       apply Filter.codiscreteWithin.mono (by tauto : Ι 0 (π / 2) ⊆ Set.univ)
       have t₀ : sin ⁻¹' {0}ᶜ ∈ Filter.codiscrete ℝ := by
@@ -48,8 +48,8 @@ theorem integral_log_sin_zero_pi_div_two : ∫ x in (0)..(π / 2), log (sin x) =
       simp_all only [Set.preimage_compl, Set.mem_compl_iff, Set.mem_preimage, Set.mem_singleton_iff,
         sin_two_mul, ne_eq, mul_eq_zero, OfNat.ofNat_ne_zero, or_self, not_false_eq_true, log_mul]
       ring
-    _ = (∫ x in (0)..(π / 2), log (sin (2 * x))) - π / 2 * log 2
-        - ∫ x in (0)..(π / 2), log (cos x) := by
+    _ = (∫ x in 0..(π / 2), log (sin (2 * x))) - π / 2 * log 2
+        - ∫ x in 0..(π / 2), log (cos x) := by
       rw [intervalIntegral.integral_sub _ _,
         intervalIntegral.integral_sub _ intervalIntegrable_const,
         intervalIntegral.integral_const]
@@ -58,8 +58,8 @@ theorem integral_log_sin_zero_pi_div_two : ∫ x in (0)..(π / 2), log (sin x) =
       · apply IntervalIntegrable.sub _ intervalIntegrable_const
         simpa using (intervalIntegrable_log_sin (a := 0) (b := π)).comp_mul_left
       · exact intervalIntegrable_log_cos
-    _ = (∫ x in (0)..(π / 2), log (sin (2 * x)))
-        - π / 2 * log 2 - ∫ x in (0)..(π / 2), log (sin x) := by
+    _ = (∫ x in 0..(π / 2), log (sin (2 * x)))
+        - π / 2 * log 2 - ∫ x in 0..(π / 2), log (sin x) := by
       simp [← sin_pi_div_two_sub,
         intervalIntegral.integral_comp_sub_left (fun x ↦ log (sin x)) (π / 2)]
     _ = -log 2 * π / 2 := by
@@ -72,7 +72,7 @@ theorem integral_log_sin_zero_pi_div_two : ∫ x in (0)..(π / 2), log (sin x) =
 /--
 The integral of `log ∘ sin` on `0 … π` equals `-log 2 * π`.
 -/
-theorem integral_log_sin_zero_pi : ∫ x in (0)..π, log (sin x) = -log 2 * π := by
+theorem integral_log_sin_zero_pi : ∫ x in 0..π, log (sin x) = -log 2 * π := by
   rw [integral_log_sin_zero_pi_eq_two_mul_integral_log_sin_zero_pi_div_two,
     integral_log_sin_zero_pi_div_two]
   ring

Mathlib/Analysis/SpecialFunctions/Pow/Integral.lean

@@ -49,7 +49,7 @@ theorem lintegral_rpow_eq_lintegral_meas_le_mul
     ∫⁻ ω, ENNReal.ofReal (f ω ^ p) ∂μ =
       ENNReal.ofReal p * ∫⁻ t in Ioi 0, μ {a : α | t ≤ f a} * ENNReal.ofReal (t ^ (p - 1)) := by
   have one_lt_p : -1 < p - 1 := by linarith
-  have obs : ∀ x : ℝ, ∫ t : ℝ in (0)..x, t ^ (p - 1) = x ^ p / p := by
+  have obs : ∀ x : ℝ, ∫ t : ℝ in 0..x, t ^ (p - 1) = x ^ p / p := by
     intro x
     rw [integral_rpow (Or.inl one_lt_p)]
     simp [Real.zero_rpow p_pos.ne.symm]

Mathlib/MeasureTheory/Integral/CircleAverage.lean

@@ -48,14 +48,14 @@ Define `circleAverage f c R` as the average value of `f` on the circle with cent
 defined in `circleIntegral` (integrating with respect to `dz`).
 -/
 noncomputable def circleAverage : E :=
-  (2 * π)⁻¹ • ∫ θ in (0)..2 * π, f (circleMap c R θ)
+  (2 * π)⁻¹ • ∫ θ in 0..2 * π, f (circleMap c R θ)
 
 lemma circleAverage_def :
-    circleAverage f c R = (2 * π)⁻¹ • ∫ θ in (0)..2 * π, f (circleMap c R θ) := rfl
+    circleAverage f c R = (2 * π)⁻¹ • ∫ θ in 0..2 * π, f (circleMap c R θ) := rfl
 
 /-- Expression of `circleAverage´ in terms of interval averages. -/
 lemma circleAverage_eq_intervalAverage :
-    circleAverage f c R = ⨍ θ in (0)..2 * π, f (circleMap c R θ) := by
+    circleAverage f c R = ⨍ θ in 0..2 * π, f (circleMap c R θ) := by
   simp [circleAverage, interval_average_eq]
 
 /-- Interval averages for zero radii equal values at the center point. -/
@@ -103,7 +103,7 @@ theorem circleAverage_eq_circleIntegral {F : Type*} [NormedAddCommGroup F] [Norm
 
 /-- Circle averages do not change when shifting the angle. -/
 lemma circleAverage_eq_integral_add (η : ℝ) :
-    circleAverage f c R = (2 * π)⁻¹ • ∫ θ in (0)..2 * π, f (circleMap c R (θ + η)) := by
+    circleAverage f c R = (2 * π)⁻¹ • ∫ θ in 0..2 * π, f (circleMap c R (θ + η)) := by
   rw [intervalIntegral.integral_comp_add_right (fun θ ↦ f (circleMap c R θ))]
   have t₀ : (fun θ ↦ f (circleMap c R θ)).Periodic (2 * π) :=
     fun x ↦ by simp [periodic_circleMap c R x]