1e02c08111
Upstreaming of basic material on `List.Pairwise` and `List.Nodup`. More complete API to follow later, this is just a first approximation of what leansat will need.
10 lines
463 B
Text
10 lines
463 B
Text
variable (R : α → α → Prop)
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inductive List.Pairwise' : List α → Prop
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| nil : Pairwise' []
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| cons : ∀ {a : α} {l : List α}, (∀ {a} (_ : a' ∈ l), R a a') → Pairwise' l → Pairwise' (a :: l)
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theorem pairwise_append {l₁ l₂ : List α} :
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(l₁ ++ l₂).Pairwise' R ↔ l₁.Pairwise' R ∧ l₂.Pairwise' R ∧ ∀ {a} (_ : a ∈ l₁), ∀ {b} (_ : b ∈ l₂), R a b := by
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induction l₁ <;> simp [*, and_left_comm]
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repeat sorry
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