OAI/Combinatorics/SharpThreshold/BlockOrbit.lean

GitHub source file

14 declarations, 0 contain sorry, 0 declared as axioms

  1. def OAI.Problem313.extendBlockPerm line 12

    Source documentation

    A permutation of a block, extended by the identity away from the block.

    def extendBlockPerm {α : Type u} [DecidableEq α] (B : Finset α)
        (σ : Equiv.Perm B) : Equiv.Perm α :=
    …
  2. theorem OAI.Problem313.extendBlockPerm_apply_mem line 17
  3. theorem OAI.Problem313.extendBlockPerm_apply_notMem line 23
  4. theorem OAI.Problem313.exists_blockPerm_map line 29

    Source documentation

    Equal-sized subsets of a block can be mapped to one another while fixing its complement.

    theorem exists_blockPerm_map {α : Type u} [DecidableEq α]
        (B s t : Finset α) (hs : s ⊆ B) (ht : t ⊆ B) (hc : s.card = t.card) :
        ∃ σ : Equiv.Perm B, s.map (extendBlockPerm B σ).toEmbedding = t := by
    …

    Mentions: OAI.Problem313.extendBlockPerm

  5. theorem OAI.Problem313.extendBlockPerm_map_disjoint line 48

    Source documentation

    A block permutation fixes any finite set disjoint from the block.

    theorem extendBlockPerm_map_disjoint {α : Type u} [DecidableEq α]
        (B s : Finset α) (σ : Equiv.Perm B) (hs : Disjoint s B) :
        s.map (extendBlockPerm B σ).toEmbedding = s := by
    …

    Mentions: OAI.Problem313.extendBlockPerm

  6. theorem OAI.Problem313.exists_blockPerm_map_of_sdiff_eq line 65

    Source documentation

    Equal-sized finite sets with the same exterior part are in the same block orbit.

    theorem exists_blockPerm_map_of_sdiff_eq {α : Type u} [DecidableEq α]
        (B s t : Finset α) (hc : s.card = t.card) (hout : s \ B = t \ B) :
        ∃ σ : Equiv.Perm B, s.map (extendBlockPerm B σ).toEmbedding = t := by
    …

    Mentions: OAI.Problem313.extendBlockPerm

  7. theorem OAI.Problem313.exists_blockPerm_permEdge line 87

    Source documentation

    Edge transport preserving the vertices outside the selected block.

    theorem exists_blockPerm_permEdge {n : ℕ} (B : Finset (Fin n))
        (e e' : GraphEdge n) (hout : e.1 \ B = e'.1 \ B) :
        ∃ σ : Equiv.Perm B, permEdge (extendBlockPerm B σ) e = e' := by
    …

    Mentions: OAI.Problem313.GraphEdge, OAI.Problem313.permEdge, OAI.Problem313.extendBlockPerm

  8. theorem OAI.Problem313.permEdge_extendBlockPerm_of_disjoint line 95

    Source documentation

    Every edge not touching the block is fixed pointwise by the block action.

    theorem permEdge_extendBlockPerm_of_disjoint {n : ℕ} (B : Finset (Fin n))
        (σ : Equiv.Perm B) (e : GraphEdge n) (he : Disjoint e.1 B) :
        permEdge (extendBlockPerm B σ) e = e := by
    …

    Mentions: OAI.Problem313.GraphEdge, OAI.Problem313.permEdge, OAI.Problem313.extendBlockPerm

  9. theorem OAI.Problem313.extendBlockPerm_mem_iff line 101
  10. theorem OAI.Problem313.extendBlockPerm_map_block line 111
  11. theorem OAI.Problem313.extendBlockPerm_sdiff line 121

    Source documentation

    Block-supported permutations leave the exterior part of every finite set unchanged.

    theorem extendBlockPerm_sdiff {α : Type u} [DecidableEq α]
        (B s : Finset α) (σ : Equiv.Perm B) :
        s.map (extendBlockPerm B σ).toEmbedding \ B = s \ B := by
    …

    Mentions: OAI.Problem313.extendBlockPerm

  12. theorem OAI.Problem313.exists_blockPerm_permEdge_iff line 131

    Source documentation

    Two graph edges belong to the same block orbit exactly when their exterior vertices agree.

    theorem exists_blockPerm_permEdge_iff {n : ℕ} (B : Finset (Fin n))
        (e e' : GraphEdge n) :
        (∃ σ : Equiv.Perm B, permEdge (extendBlockPerm B σ) e = e') ↔
          e.1 \ B = e'.1 \ B := by
    …

    Mentions: OAI.Problem313.GraphEdge, OAI.Problem313.permEdge, OAI.Problem313.extendBlockPerm

  13. theorem OAI.Problem313.extendBlockPerm_symm line 141
  14. theorem OAI.Problem313.permuteConfig_extendBlockPerm_apply_of_disjoint line 147

    Source documentation

    Relabeling inside the block leaves each exterior configuration coordinate unchanged.

    theorem permuteConfig_extendBlockPerm_apply_of_disjoint {n : ℕ}
        (B : Finset (Fin n)) (σ : Equiv.Perm B) (x : GraphConfig n)
        (e : GraphEdge n) (he : Disjoint e.1 B) :
        permuteConfig (extendBlockPerm B σ) x e = x e := by
    …

    Mentions: OAI.Problem313.GraphConfig, OAI.Problem313.GraphEdge, OAI.Problem313.permuteConfig, OAI.Problem313.extendBlockPerm