17 lines
472 B
Text
17 lines
472 B
Text
universe u
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class MyClass (α : Type u) extends LE α where
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sup : α → α → α
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le_refl : ∀ a : α, a ≤ a
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sup_of_le_left : ∀ a b : α, b ≤ a → sup a b = a
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instance : MyClass Prop where
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le_refl _ := id
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sup_of_le_left _ _ h := propext ⟨Or.rec id h, Or.inl⟩
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/--
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info: Try this: simp only [MyClass.le_refl, MyClass.sup_of_le_left]
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-/
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#guard_msgs in
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example : MyClass.sup False False = False := by
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simp? [MyClass.sup_of_le_left, MyClass.le_refl]
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