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14
15 include "logic/equality.ma".
16 include "sets/setoids.ma".
17
18 ninductive nat: Type[0] ≝
19    O: nat
20  | S: nat → nat.
21
22 ndefinition NAT: setoid.
23  napply mk_setoid [ napply nat | napply EQ]
24 nqed.
25
26 unification hint 0 ((λx,y.True) (carr NAT) nat).