8 lines
226 B
Text
8 lines
226 B
Text
class AddIdepotent (α : Type u) [Add α] : Prop where
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add_id (x : α) : x + x = x
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export AddIdepotent (add_id)
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theorem tst [Add α] [AddIdepotent α] (x : α) : id (x + x + x) = x := by
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rw [add_id, add_id]
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simp [id]
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