Index - Z
| Zero | Data.PeanoNat, Data.Type.Witness | 
| ZeroGreaterEqual | Data.Type.Witness.Specific.PeanoNat, Data.Type.Witness | 
| zeroNaturalType | Data.Type.Witness.Specific.Natural, Data.Type.Witness | 
| ZeroType | Data.Type.Witness.Specific.PeanoNat, Data.Type.Witness |