7 lines
276 B
Text
7 lines
276 B
Text
inductive imf (f : nat → nat) : nat → Type
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| mk1 : ∀ (a : nat), imf (f a)
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| mk2 : imf (f 0 + 1)
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definition inv_2 (f : nat → nat) : ∀ (b : nat), imf f b → {x : nat // x > b} → nat
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| .(f a) (imf.mk1 .f a) x := a
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| .(f 0 + 1) (imf.mk2 .f) x := subtype.val x
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