19 lines
533 B
Text
19 lines
533 B
Text
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import data.list
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constant R : Π {A : Type}, A → A → Prop
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infix `~`:50 := R
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example {A : Type} {a b c d : list nat} (H₁ : a ~ b) (H₂ : b = c) (H₃ : c = d) : a ~ d :=
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calc a ~ b : H₁
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... = c : H₂
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... = d : H₃
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example {A : Type} {a b c d : list nat} (H₁ : a = b) (H₂ : b = c) (H₃ : c ~ d) : a ~ d :=
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calc a = b : H₁
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... = c : H₂
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... ~ d : H₃
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example {A : Type} {a b c d : list nat} (H₁ : a = b) (H₂ : b ~ c) (H₃ : c = d) : a ~ d :=
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calc a = b : H₁
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... ~ c : H₂
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... = d : H₃
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