8979663164
Motivation: if the explicit part matches (what the user sees), then the implicit part must morally match too. If it doesn't because of reducibility setting, the behavior is usually counterintuitive.
27 lines
607 B
Text
27 lines
607 B
Text
namespace test
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universes u v
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def vector (α : Type u) (n : ℕ) := { l : list α // list.length l = n }
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namespace vector
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open subtype list
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variable {α : Type u}
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def nil : vector α 0 := ⟨[], rfl⟩
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def append {m n : ℕ} : vector α m → vector α n → vector α (m + n)
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| ⟨v, _⟩ ⟨w, _⟩ := ⟨v ++ w, by abstract {simph}⟩
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end vector
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section
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open vector
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variable α : Type u
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variables m n k : ℕ
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variable v : vector α m
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variable w : vector α n
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theorem append_nil : append v nil = v :=
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by cases v; simp [vector.append, vector.nil]; reflexivity
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end
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end test
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