2 lines
179 B
Text
2 lines
179 B
Text
theorem perm.perm_erase_dup_of_perm [congr] : ∀ {A : Type} [H : decidable_eq A] {l₁ l₂ : list A}, l₁ ~ l₂ → erase_dup l₁ ~ erase_dup l₂ :=
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λ A H l₁ l₂, sorry
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