Changes
1 changed files (+13/-15)
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@@ -15,7 +15,7 @@ lemma geom_sum (b : ℝ) (N : ℕ) (h₁ : 2 ≤ N) (h₂ : 2 ≤ b) : ∑ a ∈grind exact h₁ _ = 1 / (b - 1) - 1 / b - b / (b ^ N * (b - 1)) := by have h₃ : b - 1 ≠ 0 := by have : b - 1 ≠ 0 := by linarith field_simp ring
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@@ -127,17 +127,17 @@ theorem double_sum : converges_to (fun N : ℕ => ∑ a ∈ Ico 2 N, ∑ b ∈ Ihave h₃ : 1 < 1 + ε - 1 / (n - 1) - (n - 2) / 2 ^ (n - 1) := by suffices 1 / (n - 1) + (n - 2) / 2 ^ (n - 1) < ε by linarith if hε : 3 / 2 < ε then have h₄ : 2 ≤ (n : ℝ) := Nat.ofNat_le_cast.mpr h₁ have h₅ : 1 / ((n : ℝ) - 1) ≤ 1 := by have : 2 ≤ (n : ℝ) := Nat.ofNat_le_cast.mpr h₁ have : 1 / ((n : ℝ) - 1) ≤ 1 := by refine (div_le_one₀ ?_).mpr (by linarith) linarith suffices ((n : ℝ) - 2) / 2 ^ (n - 1) ≤ 1 / 2 by linarith have h₆ : 2 * (n - 2) ≤ 2 ^ (n - 1) := by if h₇ : n = 2 then simp [h₇] have h₄ : 2 * (n - 2) ≤ 2 ^ (n - 1) := by if h₅ : n = 2 then simp [h₅] else exact exp_larger n (by omega) rw [mul_comm, ←one_mul (2 ^ (n - 1))] at h₆ rw [mul_comm, ←one_mul (2 ^ (n - 1))] at h₄ exact (div_le_div_iff₀ (by norm_num) (by norm_num)).mpr (by norm_cast) else simp at hε
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@@ -158,10 +158,10 @@ theorem double_sum : converges_to (fun N : ℕ => ∑ a ∈ Ico 2 N, ∑ b ∈ Iexact exp_larger' n (by omega) apply lt_sub_iff_add_lt'.mp have h₅ : 3 / (n : ℝ) - 1 / (n - 1) = (2 * n - 3) / (n * (n - 1)) := by have h₆ : (n : ℝ) ≠ 0 := by have : (n : ℝ) ≠ 0 := by rw [Nat.cast_ne_zero] omega have h₇ : (n : ℝ) - 1 ≠ 0 := by have : (n : ℝ) - 1 ≠ 0 := by grind field_simp ring
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@@ -177,8 +177,7 @@ theorem double_sum : converges_to (fun N : ℕ => ∑ a ∈ Ico 2 N, ∑ b ∈ Isimp have h₉ : ↑(n - 2) = (n : ℝ) - 2 := by norm_cast rw [h₇, h₈, h₉] at h₄ exact h₄ rwa [h₇, h₈, h₉] at h₄ have h₇ : 0 < (2 : ℝ) ^ (n - 1) := by norm_num exact (div_lt_div_iff₀ h₇ (by nlinarith)).mpr h₆
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@@ -195,11 +194,10 @@ theorem double_sum : converges_to (fun N : ℕ => ∑ a ∈ Ico 2 N, ∑ b ∈ Ihave h₃ : ∀ b ∈ Ico 2 n, 0 < (1 : ℝ) / (b ^ (n - 1) * (b - 1)) := by intro b bico field_simp have h₄ : 2 ≤ b := List.left_le_of_mem_range' bico have h₅ : 1 < (b : ℝ) := Nat.one_lt_cast.mpr h₄ have h₆ : 0 < (b : ℝ) ^ (n - 1) := by have : 1 < (b : ℝ) := Nat.one_lt_cast.mpr (List.left_le_of_mem_range' bico) have h₄ : 0 < (b : ℝ) ^ (n - 1) := by apply pow_pos (by linarith) exact mul_pos h₆ (by linarith) exact mul_pos h₄ (by linarith) have h₄ : 0 ≤ ∑ b ∈ Ico 2 n, (1 : ℝ) / (b ^ (n - 1) * (b - 1)) := sum_nonneg (fun b a => le_of_lt (h₃ b a)) ring_nf at h₄ field_simp at h₄
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