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20 lines
428 B
Idris
20 lines
428 B
Idris
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-- adapted from:
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-- Andreas Abel, Thorsten Altenkirch
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-- A predicative analysis of structural recursion
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-- https://doi.org/10.1017/S0956796801004191
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data Ord : Type where
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O : Ord
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S : Ord -> Ord
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Lim : (Nat -> Ord) -> Ord
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total
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addord : Ord -> Ord -> Ord
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addord_lim : (Nat -> Ord) -> Ord -> Ord
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addord O y = y
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addord (S x) y = S (addord x y)
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addord (Lim f) y = addord_lim f y
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addord_lim f y = Lim (\z => addord (f z) y)
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