Methodology

The example in figure PC-Gender shows the different facets of the attribute .ΔGender modeled in the partitioning class ^.Gender. Partitioning classes names are prefixed with the special character combination circumflex-dot (^.). The base PC ^.Gender declares the attribute .ΔGender as Atomic Data Type (ADT) :String. The Meta Data Property (MDP) .^^mutable is set to true (T). This declares that the value for .ΔGender can change and that an entity may have more than one .Gender due to .^^multiple=T . In the animal kingdom, the earthworm is assigned .Gender(^Earthworm) = bisexual because each earthworm has both male and female sex organs throughout its whole life. Thus, each individual earthworm would inherit the values ‘male’ and ‘female’ for .ΔGender via VAP. The ‘orange clownfish’ is initially ‘male’ (^ANM-Clownfish, »is, ^.male) and can later change its gender to ‘female’. This explains why the particular >ANM-Nemos_mother can be an instance of the class ^ANM-Clownfish and an instance of the PC ^.female at the same time. You can also use (>ANM-Nemos_mother, »is-not, ^.male) to explicitly state that >ANM-Nemos_mother is ‘not male’. The »is-not forces the default values for (^ANM-Clownfish, »is, ^.male) to be withdrawn which is a requirement we generally impose for »is-not.

‘Gender’ is not just a characteristic of humans or living things in general. It can also be applied to things like ‘nuts’ and ‘bolts’. Figure pc-gender shows the generalized modeling using the partitioning class ^.Gender. This again follows the naming conventions already presented in the Preliminaries section above. The instantiation is done in such a way that, e.g.,  the class ^Mother as a subclass of ^.female would also inherit the feature (.ΔGender, female) as a Transparent Data Property (TDP). This means for all instances of ^Mother : (>M, >^is, ^Mother) ∈ KG → (>M, .ΔGender, female) ∈ KG. The .ΔGender attribute can also be inferred from Object Properties (OP). All OPs can be used for this, where the classes ^.female, ^.male, ^Woman, ^Man are defined as »hasRange. From (>P1, »Father, >P2) ∈ KG we can deduce that (>P2, .ΔGender, male) ∈ KG using (◊Father, »hasRange, ^.male). Note also that when we assign a particular to a partitioning class we use the synonym >^is instead of »pof ,e.g., (>ANM-Nemos_mother, >^is, ^.female). The reason for this is the readability is better compared to modeling »pof ^.female. Modeling the MDP .^^Particulars in the PC ^.Gender and its subclasses exhibits another advantage. E.g., the number of particulars for (^.female, .^^Particulars, 2943) can be queried with a single access saving count queries that can take seconds for very large numbers of instances.