31 lines
689 B
Text
31 lines
689 B
Text
--| `build` is the inverse of `fold`
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let build
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: ( ∀(natural : Type) →
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∀(succ : natural → natural) →
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∀(zero : natural) →
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natural
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) →
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Natural
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= Natural/build
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let example0 =
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assert
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: build
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( λ(natural : Type) →
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λ(succ : natural → natural) →
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λ(zero : natural) →
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succ (succ (succ zero))
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)
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≡ 3
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let example1 =
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assert
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: build
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( λ(natural : Type) →
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λ(succ : natural → natural) →
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λ(zero : natural) →
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zero
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)
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≡ 0
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in build
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