9 lines
318 B
Text
9 lines
318 B
Text
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def f1 (ex : Empty) {α : Type} : α :=
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Empty.rec (motive := fun _ => α) ex
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def f2 (a b : Nat) (h₁ : b = a) (h₂ : a + b = b) : a + a = b :=
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Eq.rec (motive := fun x _ => a + x = b) h₂ h₁
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def f3 (a b : Nat) (h₁ : b = a) (h₂ : a + b = b) : a + a = b :=
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Eq.recOn (motive := fun x _ => a + x = b) h₁ h₂
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