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fix(library/data/list/perm): broken theorem

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Leonardo de Moura 2015-04-11 09:42:24 -07:00
parent 1b34f40f36
commit fefddcd0f9
1 changed files with 1 additions and 1 deletions
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library/data/list/perm.lean
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@ -591,7 +591,7 @@ include H
theorem perm_union_left {l₁ l₂ : list A} (t₁ : list A) : l₁ ~ l₂ → (union l₁ t₁) ~ (union l₂ t₁) := theorem perm_union_left {l₁ l₂ : list A} (t₁ : list A) : l₁ ~ l₂ → (union l₁ t₁) ~ (union l₂ t₁) :=
assume p, perm.induction_on p assume p, perm.induction_on p
(by rewrite [union_nil]; exact !refl) (by rewrite [nil_union]; exact !refl)
(λ x l₁ l₂ p₁ r₁, by_cases (λ x l₁ l₂ p₁ r₁, by_cases
(λ xint₁ : x ∈ t₁, by rewrite [*union_cons_of_mem _ xint₁]; exact r₁) (λ xint₁ : x ∈ t₁, by rewrite [*union_cons_of_mem _ xint₁]; exact r₁)
(λ nxint₁ : x ∉ t₁, by rewrite [*union_cons_of_not_mem _ nxint₁]; exact (skip _ r₁))) (λ nxint₁ : x ∉ t₁, by rewrite [*union_cons_of_not_mem _ nxint₁]; exact (skip _ r₁)))