imo.imo2008_q2 | 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

5f25c089

(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

@@ -3,8 +3,8 @@ Copyright (c) 2021 Manuel Candales. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Manuel Candales
 -/
-import Mathbin.Data.Real.Basic
-import Mathbin.Data.Set.Finite
+import Data.Real.Basic
+import Data.Set.Finite
 
 #align_import imo.imo2008_q2 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

@@ -2,15 +2,12 @@
 Copyright (c) 2021 Manuel Candales. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Manuel Candales
-
-! This file was ported from Lean 3 source module imo.imo2008_q2
-! 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.Set.Finite
 
+#align_import imo.imo2008_q2 from "leanprover-community/mathlib"@"08b081ea92d80e3a41f899eea36ef6d56e0f1db0"
+
 /-!
 # IMO 2008 Q2

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: Manuel Candales
 
 ! This file was ported from Lean 3 source module imo.imo2008_q2
-! leanprover-community/mathlib commit 5f25c089cb34db4db112556f23c50d12da81b297
+! leanprover-community/mathlib commit 08b081ea92d80e3a41f899eea36ef6d56e0f1db0
 ! Please do not edit these lines, except to modify the commit id
 ! if you have ported upstream changes.
 -/
@@ -13,6 +13,9 @@ import Mathbin.Data.Set.Finite
 
 /-!
 # IMO 2008 Q2
+
+> THIS FILE IS SYNCHRONIZED WITH MATHLIB4.
+> Any changes to this file require a corresponding PR to mathlib4.
 (a) Prove that
           ```
           x^2 / (x-1)^2 + y^2 / (y-1)^2 + z^2 / (z-1)^2 ≥ 1

5f25c089

bump to nightly-2023-06-09-07

mathlib commit https://github.com/leanprover-community/mathlib/commit/7e5137f579de09a059a5ce98f364a04e221aabf0

16afdc39

Diff

@@ -102,7 +102,6 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions :=
             (x ^ 2 * t ^ 4 + y ^ 2 * (t + 1) ^ 4 + z ^ 2) / (t ^ 2 + t + 1) ^ 2 :=
           by rw [hx1, hy1, hz1]; field_simp
         _ = 1 := by rw [hx_t, hy_t, hz_t]; field_simp; ring
-        
     exact ⟨h₁, h₂, h₃, h₄, h₅, h₆⟩
   have hW_inf : Set.Infinite W :=
     by
@@ -133,7 +132,6 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions :=
           _ ≤ t := (le_max_left (q + 1) 1)
           _ ≤ t + t ^ 2 := by linarith [sq_nonneg t]
           _ = t * (t + 1) := by ring
-          
       exact ⟨h₁, h₂⟩
     have hK_inf : Set.Infinite K := by intro h; apply hK_not_bdd; exact Set.Finite.bddAbove h
     exact hK_inf.of_image g

5f25c089

bump to nightly-2023-06-07-01

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

176da745

Changes in mathlib4

mathlib3

mathlib4

5f25c089

chore: adapt to multiple goal linter 1 (#12338)

A PR accompanying #12339.

Zulip discussion

45f93f3f

Diff

@@ -103,9 +103,9 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions := by
         set z : ℚ := -t * (t + 1) with hz_def
         simp only [t, W, K, g, Set.mem_image, Prod.exists]
         use x, y, z; constructor
-        simp only [Set.mem_setOf_eq]
-        · use x, y, z; constructor
-          rfl
+        · simp only [Set.mem_setOf_eq]
+          use x, y, z; constructor
+          · rfl
           · use t; constructor
             · simp only [t, gt_iff_lt, lt_max_iff]; right; trivial
             exact ⟨rfl, rfl, rfl⟩

5f25c089

chore: superfluous parentheses part 2 (#12131)

Co-authored-by: Moritz Firsching <firsching@google.com>

d48d30ac

Diff

@@ -114,7 +114,7 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions := by
       have h₂ : q < t * (t + 1) := by
         calc
           q < q + 1 := by linarith
-          _ ≤ t := (le_max_left (q + 1) 1)
+          _ ≤ t := le_max_left (q + 1) 1
           _ ≤ t + t ^ 2 := by linarith [sq_nonneg t]
           _ = t * (t + 1) := by ring
       exact ⟨h₁, h₂⟩

5f25c089

chore: prepare Lean version bump with explicit simp (#10999)

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

38bce757

Diff

@@ -101,13 +101,13 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions := by
         let x : ℚ := -(t + 1) / t ^ 2
         let y : ℚ := t / (t + 1) ^ 2
         set z : ℚ := -t * (t + 1) with hz_def
-        simp only [Set.mem_image, Prod.exists]
+        simp only [t, W, K, g, Set.mem_image, Prod.exists]
         use x, y, z; constructor
         simp only [Set.mem_setOf_eq]
         · use x, y, z; constructor
           rfl
           · use t; constructor
-            · simp only [gt_iff_lt, lt_max_iff]; right; trivial
+            · simp only [t, gt_iff_lt, lt_max_iff]; right; trivial
             exact ⟨rfl, rfl, rfl⟩
         · have hg : -z = g (x, y, z) := rfl
           rw [hg, hz_def]; ring

5f25c089

chore: remove stream-of-consciousness uses of have, replace and suffices (#10640)

No changes to tactic file, it's just boring fixes throughout the library.

This follows on from #6964.

Co-authored-by: sgouezel <sebastien.gouezel@univ-rennes1.fr> Co-authored-by: Eric Wieser <wieser.eric@gmail.com>

a13e8040

Diff

@@ -72,7 +72,7 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions := by
     simp only [Set.mem_setOf_eq] at hs_in_W ⊢
     rcases hs_in_W with ⟨x, y, z, h₁, t, ht_gt_zero, hx_t, hy_t, hz_t⟩
     use x, y, z
-    have key_gt_zero : t ^ 2 + t + 1 > 0; linarith [pow_pos ht_gt_zero 2, ht_gt_zero]
+    have key_gt_zero : t ^ 2 + t + 1 > 0 := by linarith [pow_pos ht_gt_zero 2, ht_gt_zero]
     have h₂ : x ≠ 1 := by rw [hx_t]; field_simp; linarith [key_gt_zero]
     have h₃ : y ≠ 1 := by rw [hy_t]; field_simp; linarith [key_gt_zero]
     have h₄ : z ≠ 1 := by rw [hz_t]; linarith [key_gt_zero]

5f25c089

chore(Tactic/GCongr): move @[gcongr] tags around (#9393)

Add import Mathlib.Tactic.GCongr.Core to Algebra/Order/Ring/Lemmas.
Move most @[gcongr] tags next to the lemmas.

See Zulip thread

Co-authored-by: Jeremy Tan Jie Rui <reddeloostw@gmail.com>

cd4edcb7

Diff

@@ -3,6 +3,7 @@ Copyright (c) 2021 Manuel Candales. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Manuel Candales
 -/
+import Mathlib.Algebra.Parity
 import Mathlib.Data.Real.Basic
 import Mathlib.Data.Set.Finite
 import Mathlib.Tactic.FieldSimp

5f25c089

chore: split Data.Real.Basic (#8356)

Co-authored-by: Scott Morrison <scott.morrison@gmail.com>

43e32656

Diff

@@ -5,6 +5,9 @@ Authors: Manuel Candales
 -/
 import Mathlib.Data.Real.Basic
 import Mathlib.Data.Set.Finite
+import Mathlib.Tactic.FieldSimp
+import Mathlib.Tactic.Abel
+import Mathlib.Tactic.Linarith
 
 #align_import imo.imo2008_q2 from "leanprover-community/mathlib"@"5f25c089cb34db4db112556f23c50d12da81b297"

5f25c089

field_simp: Use positivity as a discharger (#6312)

The main reasons is that having h : 0 < denom in the context should suffice for field_simp to do its job, without the need to manually pass h.ne or similar.

Quite a few have := … ≠ 0 could be dropped, and some field_simp calls no longer need explicit arguments; this is promising.

This does break some proofs where field_simp was not used as a closing tactic, and it now shuffles terms around a bit different. These were fixed. Using field_simp in the middle of a proof seems rather fragile anyways.

As a drive-by contribution, positivity now knows about π > 0.

fixes: #4835

Co-authored-by: Matthew Ballard <matt@mrb.email>

6b391efa

Diff

@@ -68,10 +68,7 @@ theorem imo2008_q2b : Set.Infinite rationalSolutions := by
     simp only [Set.mem_setOf_eq] at hs_in_W ⊢
     rcases hs_in_W with ⟨x, y, z, h₁, t, ht_gt_zero, hx_t, hy_t, hz_t⟩
     use x, y, z
-    have ht_ne_zero : t ≠ 0 := ne_of_gt ht_gt_zero
-    have ht1_ne_zero : t + 1 ≠ 0; linarith [ht_gt_zero]
     have key_gt_zero : t ^ 2 + t + 1 > 0; linarith [pow_pos ht_gt_zero 2, ht_gt_zero]
-    have key_ne_zero : t ^ 2 + t + 1 ≠ 0 := ne_of_gt key_gt_zero
     have h₂ : x ≠ 1 := by rw [hx_t]; field_simp; linarith [key_gt_zero]
     have h₃ : y ≠ 1 := by rw [hy_t]; field_simp; linarith [key_gt_zero]
     have h₄ : z ≠ 1 := by rw [hz_t]; linarith [key_gt_zero]

5f25c089

feat: restore field_simp [*] (#6024)

fixes #5689

to do this we basically copy the missing functionality over from the simp internals

73761eed

Diff

@@ -38,8 +38,7 @@ theorem subst_abc {x y z : ℝ} (h : x * y * z = 1) :
     have := h.symm ▸ one_ne_zero
     simpa [not_or] using this
   have : z * (y * x) = 1 := by rw [← h]; ac_rfl
-  -- Porting note: Originally `field_simp [*]`, but `*` doesn't work (see #5689)
-  field_simp [hx, this]
+  field_simp [*]
 #align imo2008_q2.subst_abc Imo2008Q2.subst_abc
 
 theorem imo2008_q2a (x y z : ℝ) (h : x * y * z = 1) (hx : x ≠ 1) (hy : y ≠ 1) (hz : z ≠ 1) :

5f25c089

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

@@ -2,15 +2,12 @@
 Copyright (c) 2021 Manuel Candales. All rights reserved.
 Released under Apache 2.0 license as described in the file LICENSE.
 Authors: Manuel Candales
-
-! This file was ported from Lean 3 source module imo.imo2008_q2
-! leanprover-community/mathlib commit 5f25c089cb34db4db112556f23c50d12da81b297
-! 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.Set.Finite
 
+#align_import imo.imo2008_q2 from "leanprover-community/mathlib"@"5f25c089cb34db4db112556f23c50d12da81b297"
+
 /-!
 # IMO 2008 Q2
 (a) Prove that

5f25c089

chore: restore simp lemmas in Logic.Equiv.Set (#5643)

Two simp lemmas were removed with porting notes because the LHS already simplified. I think instead they should have had their priority increased.

Co-authored-by: Scott Morrison <scott.morrison@gmail.com> Co-authored-by: Johan Commelin <johan@commelin.net>

57535b03

`imo.imo2008_q2` ⟷ `Archive.Imo.Imo2008Q2`

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 7 + 274

imo.imo2008_q2 ⟷ Archive.Imo.Imo2008Q2

Changes since the initial port

Changes in mathlib3

Changes in mathlib3port

Changes in mathlib4

Dependencies 7 + 274

`imo.imo2008_q2` ⟷ `Archive.Imo.Imo2008Q2`