Constants Constants are used to identify instances that may be commonly used with an ontology. In this section, each constant is grouped under its category. Male Female Inferences Inference rules are used to determine what additional facts can be implied if other facts are known. Child and parent are inverse relations. All fathers are parents.
All mothers are parents.
The male parent of of a child is their father. The female parent of of a child is their mother. Sibling is a symetric relation. Either of the two major forms of individuals that occur in many species and that are distinguished respectively as female or male. The age of a person in years.