20 lines
476 B
Text
20 lines
476 B
Text
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open nat
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inductive vec (A : Type) : nat → Type :=
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nil {} : vec A zero,
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cons : Π {n}, A → vec A n → vec A (succ n)
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namespace vec
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variables {A B C : Type}
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variables {n m : nat}
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notation a :: b := cons a b
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protected definition destruct (v : vec A (succ n)) {P : Π {n : nat}, vec A (succ n) → Type}
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(H : Π {n : nat} (h : A) (t : vec A n), P (h :: t)) : P v :=
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begin
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cases v with (n', h', t'),
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apply (H h' t')
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end
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end vec
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