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[Merged by Bors] - feat: definition and properties of the Turán graph#9645

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turandefs
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[Merged by Bors] - feat: definition and properties of the Turán graph#9645
Parcly-Taxel wants to merge 18 commits intomasterfrom
turandefs

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@Parcly-Taxel Parcly-Taxel commented Jan 11, 2024

The first part of the main file in #9317.


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@Parcly-Taxel Parcly-Taxel added blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) t-combinatorics Combinatorics labels Jan 11, 2024
@ghost ghost added merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) and removed blocked-by-other-PR This PR depends on another PR (this label is automatically managed by a bot) labels Jan 13, 2024
@ghost ghost removed the merge-conflict The PR has a merge conflict with master, and needs manual merging. (this label is managed by a bot) label Jan 14, 2024
Comment on lines +88 to +89
convert Nat.lt.base _
convert G.card_edgeFinset_sup_edge na ne
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Is there a nicer way to do these steps? rw [G.card_edgeFinset_sup_edge na ne, Nat.lt.base] doesn't work because the inner instances corresponding to the Sup don't match.

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@YaelDillies YaelDillies Mar 22, 2024

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I fixed it (by generalising the fintype assumptions appearing on the LHS of earlier lemmas) and then found a golf which made the fix redundant. Here's the fixed ungolfed version for your instruction:

theorem not_cliqueFree_of_isTuranMaximal (hn : r ≤ Fintype.card V) (hG : IsTuranMaximal G r) :
    ¬G.CliqueFree r := by
  by_contra cf
  obtain ⟨K, _, rfl⟩ := exists_smaller_set (univ : Finset V) r hn
  have := (G.isNClique_iff).not.mp (cf K)
  simp_rw [and_true, IsClique, Set.Pairwise, not_forall] at this
  obtain ⟨a, _, b, _, ne, na⟩ := this
  refine not_not_intro hG ?_
  simp_rw [IsTuranMaximal, hG.1, true_and]; push_neg
  use G ⊔ edge a b, inferInstance, cf.sup_edge a b
  rw [card_edgeFinset_sup_edge]
  exacts [lt_add_one _, na, ne]

@Parcly-Taxel Parcly-Taxel requested review from kmill and sgouezel March 20, 2024 01:06
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Thanks!

maintainer merge

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🚀 Pull request has been placed on the maintainer queue by YaelDillies.

@github-actions github-actions bot added the maintainer-merge A reviewer has approved the changed; awaiting maintainer approval. label Mar 22, 2024
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Thanks 🎉

bors merge

@ghost ghost added ready-to-merge This PR has been sent to bors. and removed awaiting-review labels Mar 23, 2024
mathlib-bors bot pushed a commit that referenced this pull request Mar 23, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
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mathlib-bors bot commented Mar 23, 2024

Build failed (retrying...):

mathlib-bors bot pushed a commit that referenced this pull request Mar 23, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
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mathlib-bors bot commented Mar 23, 2024

Pull request successfully merged into master.

Build succeeded:

@mathlib-bors mathlib-bors bot changed the title feat: definition and properties of the Turán graph [Merged by Bors] - feat: definition and properties of the Turán graph Mar 23, 2024
@mathlib-bors mathlib-bors bot closed this Mar 23, 2024
@mathlib-bors mathlib-bors bot deleted the turandefs branch March 23, 2024 08:16
utensil pushed a commit that referenced this pull request Mar 26, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
xgenereux pushed a commit that referenced this pull request Apr 15, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
atarnoam pushed a commit that referenced this pull request Apr 16, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
uniwuni pushed a commit that referenced this pull request Apr 19, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
callesonne pushed a commit that referenced this pull request Apr 22, 2024
The first part of the main file in #9317.



Co-authored-by: Yaël Dillies <yael.dillies@gmail.com>
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4 participants