imo.imo1975_q1 | Mathlib porting status

Changes since the initial port

The following section lists changes to this file in mathlib3 and mathlib4 that occured after the initial port. Most recent changes are shown first. Hovering over a commit will show all commits associated with the same mathlib3 commit.

Changes in mathlib3

30882647

(last sync)

Changes in mathlib3port

mathlib3

mathlib3port

08b081ea

bump to nightly-2023-09-24-06

mathlib commit https://github.com/leanprover-community/mathlib/commit/ce64cd319bb6b3e82f31c2d38e79080d377be451

5655435f

Diff

@@ -3,10 +3,10 @@ Copyright (c) 2022 Mantas Bakšys. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Mantas Bakšys
 -/
-import Mathbin.Data.Real.Basic
-import Mathbin.Data.Nat.Interval
-import Mathbin.Algebra.Order.Rearrangement
-import Mathbin.Algebra.BigOperators.Ring
+import Data.Real.Basic
+import Data.Nat.Interval
+import Algebra.Order.Rearrangement
+import Algebra.BigOperators.Ring
 
 #align_import imo.imo1975_q1 from "leanprover-community/mathlib"@"08b081ea92d80e3a41f899eea36ef6d56e0f1db0"

08b081ea

bump to nightly-2023-07-20-09

mathlib commit https://github.com/leanprover-community/mathlib/commit/8ea5598db6caeddde6cb734aa179cc2408dbd345

9c56d0dd

Diff

@@ -2,17 +2,14 @@
 Copyright (c) 2022 Mantas Bakšys. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Mantas Bakšys
-
-! This file was ported from Lean 3 source module imo.imo1975_q1
-! leanprover-community/mathlib commit 08b081ea92d80e3a41f899eea36ef6d56e0f1db0
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathbin.Data.Real.Basic
 import Mathbin.Data.Nat.Interval
 import Mathbin.Algebra.Order.Rearrangement
 import Mathbin.Algebra.BigOperators.Ring
 
+#align_import imo.imo1975_q1 from "leanprover-community/mathlib"@"08b081ea92d80e3a41f899eea36ef6d56e0f1db0"
+
 /-!
 # IMO 1975 Q1

08b081ea

bump to nightly-2023-07-17-03

mathlib commit https://github.com/leanprover-community/mathlib/commit/bf2428c9486c407ca38b5b3fb10b87dad0bc99fa

a159b65f

Diff

@@ -4,7 +4,7 @@ Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Mantas Bakšys
 
 ! This file was ported from Lean 3 source module imo.imo1975_q1
-! leanprover-community/mathlib commit 308826471968962c6b59c7ff82a22757386603e3
+! leanprover-community/mathlib commit 08b081ea92d80e3a41f899eea36ef6d56e0f1db0
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -16,6 +16,9 @@ import Mathbin.Algebra.BigOperators.Ring
 /-!
 # IMO 1975 Q1
 
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
+
 Let `x₁, x₂, ... , xₙ` and `y₁, y₂, ... , yₙ` be two sequences of real numbers, such that
 `x₁ ≥ x₂ ≥ ... ≥ xₙ` and `y₁ ≥ y₂ ≥ ... ≥ yₙ`. Prove that if `z₁, z₂, ... , zₙ` is any permutation
 of `y₁, y₂, ... , yₙ`, then `∑ (xᵢ - yᵢ)^2 ≤ ∑ (xᵢ - zᵢ)^2`

30882647

bump to nightly-2023-06-13-21

mathlib commit https://github.com/leanprover-community/mathlib/commit/9fb8964792b4237dac6200193a0d533f1b3f7423

829520ac

Diff

@@ -38,8 +38,6 @@ variable (hx : AntitoneOn x (Finset.Icc 1 n))
 
 variable (hy : AntitoneOn y (Finset.Icc 1 n))
 
-include hx hy hσ
-
 theorem imo1975_q1 :
     ∑ i in Finset.Icc 1 n, (x i - y i) ^ 2 ≤ ∑ i in Finset.Icc 1 n, (x i - y (σ i)) ^ 2 :=
   by

30882647

bump to nightly-2023-06-10-07

mathlib commit https://github.com/leanprover-community/mathlib/commit/a3e83f0fa4391c8740f7d773a7a9b74e311ae2a3

3fdc57bc

Diff

@@ -41,11 +41,11 @@ variable (hy : AntitoneOn y (Finset.Icc 1 n))
 include hx hy hσ
 
 theorem imo1975_q1 :
-    (∑ i in Finset.Icc 1 n, (x i - y i) ^ 2) ≤ ∑ i in Finset.Icc 1 n, (x i - y (σ i)) ^ 2 :=
+    ∑ i in Finset.Icc 1 n, (x i - y i) ^ 2 ≤ ∑ i in Finset.Icc 1 n, (x i - y (σ i)) ^ 2 :=
   by
   simp only [sub_sq, Finset.sum_add_distrib, Finset.sum_sub_distrib]
   -- a finite sum is invariant if we permute the order of summation
-  have hσy : (∑ i : ℕ in Finset.Icc 1 n, y i ^ 2) = ∑ i : ℕ in Finset.Icc 1 n, y (σ i) ^ 2 := by
+  have hσy : ∑ i : ℕ in Finset.Icc 1 n, y i ^ 2 = ∑ i : ℕ in Finset.Icc 1 n, y (σ i) ^ 2 := by
     rw [← Equiv.Perm.sum_comp σ (Finset.Icc 1 n) _ hσ]
   -- let's cancel terms appearing on both sides
   norm_num [hσy, mul_assoc, ← Finset.mul_sum]

30882647

bump to nightly-2023-06-07-01

mathlib commit https://github.com/leanprover-community/mathlib/commit/a3209ddf94136d36e5e5c624b10b2a347cc9d090

176da745

Changes in mathlib4

mathlib3

mathlib4

30882647

chore(*): remove empty lines between variable statements (#11418)

Empty lines were removed by executing the following Python script twice

import os
import re


# Loop through each file in the repository
for dir_path, dirs, files in os.walk('.'):
  for filename in files:
    if filename.endswith('.lean'):
      file_path = os.path.join(dir_path, filename)

      # Open the file and read its contents
      with open(file_path, 'r') as file:
        content = file.read()

      # Use a regular expression to replace sequences of "variable" lines separated by empty lines
      # with sequences without empty lines
      modified_content = re.sub(r'(variable.*\n)\n(variable(?! .* in))', r'\1\2', content)

      # Write the modified content back to the file
      with open(file_path, 'w') as file:
        file.write(modified_content)

75c86f04

Diff

@@ -30,9 +30,7 @@ open scoped BigOperators
 /- Let `n` be a natural number, `x` and `y` be as in the problem statement and `σ` be the
 permutation of natural numbers such that `z = y ∘ σ` -/
 variable (n : ℕ) (σ : Equiv.Perm ℕ) (hσ : {x | σ x ≠ x} ⊆ Finset.Icc 1 n) (x y : ℕ → ℝ)
-
 variable (hx : AntitoneOn x (Finset.Icc 1 n))
-
 variable (hy : AntitoneOn y (Finset.Icc 1 n))
 
 theorem imo1975_q1 :

30882647

feat: fix norm num with arguments (#6600)

norm_num was passing the wrong syntax node to elabSimpArgs when elaborating, which essentially had the effect of ignoring all arguments it was passed, i.e. norm_num [add_comm] would not try to commute addition in the simp step. The fix itself is very simple (though not obvious to debug!), probably using TSyntax more would help avoid such issues in future.

Due to this bug many norm_num [blah] became rw [blah]; norm_num or similar, sometimes with porting notes, sometimes not, we fix these porting notes and other regressions during the port also.

Interestingly cancel_denoms uses norm_num [<- mul_assoc] internally, so cancel_denoms also got stronger with this change.

49a849ef

Diff

@@ -42,8 +42,8 @@ theorem imo1975_q1 :
   have hσy : ∑ i : ℕ in Finset.Icc 1 n, y i ^ 2 = ∑ i : ℕ in Finset.Icc 1 n, y (σ i) ^ 2 := by
     rw [← Equiv.Perm.sum_comp σ (Finset.Icc 1 n) _ hσ]
   -- let's cancel terms appearing on both sides
-  rw [hσy, add_le_add_iff_right, ← neg_le_neg_iff, neg_sub, neg_sub, sub_le_sub_iff_right]
-  simp_rw [mul_assoc, ← Finset.mul_sum]; norm_num
+  rw [hσy, add_le_add_iff_right, sub_le_sub_iff_left]
+  simp only [gt_iff_lt, Nat.lt_one_iff, mul_assoc, ← Finset.mul_sum, zero_lt_two, mul_le_mul_left]
   -- what's left to prove is a version of the rearrangement inequality
   apply MonovaryOn.sum_mul_comp_perm_le_sum_mul _ hσ
   -- finally we need to show that `x` and `y` 'vary' together on `[1, n]` and this is due to both of

30882647

chore: script to replace headers with #align_import statements (#5979)

depends on: #5966

Co-authored-by: Eric Wieser <wieser.eric@gmail.com> Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

89aa3a3b

Diff

@@ -2,17 +2,14 @@
 Copyright (c) 2022 Mantas Bakšys. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Mantas Bakšys
-
-! This file was ported from Lean 3 source module imo.imo1975_q1
-! leanprover-community/mathlib commit 308826471968962c6b59c7ff82a22757386603e3
-! Please do not edit these lines, except to modify the commit id
-! if you have ported upstream changes.
 -/
 import Mathlib.Data.Real.Basic
 import Mathlib.Data.Nat.Interval
 import Mathlib.Algebra.Order.Rearrangement
 import Mathlib.Algebra.BigOperators.Ring
 
+#align_import imo.imo1975_q1 from "leanprover-community/mathlib"@"308826471968962c6b59c7ff82a22757386603e3"
+
 /-!
 # IMO 1975 Q1

30882647

feat: port MeasureTheory.Function.ConditionalExpectation.Basic (#4898)

529b276a

`imo.imo1975_q1` ⟷ `Archive.Imo.Imo1975Q1`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 8 + 300

imo.imo1975_q1 ⟷ Archive.Imo.Imo1975Q1

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 8 + 300

`imo.imo1975_q1` ⟷ `Archive.Imo.Imo1975Q1`