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