Created
September 9, 2013 18:47
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Definition that isn't strictly positive according to Agda or Coq, but is accepted by Idris (:total ElimT says ElimT is total, which requires not using non-SP types)
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| data T : Type -> Type where | |
| c1 : T Nat | |
| c2 : T (T Nat) | |
| ElimT : (A : Type) -> T A -> A | |
| ElimT _ c1 = 3 | |
| ElimT _ c2 = c1 |
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Agda and Coq reject this as non-strictly-positive due to the use of T as an index to itself in the type of c2. Totality checking says ElimT is total, which the manual says requires it not to use non-SP types.