Having a certain order of complexity or being defined on a certain logical level (
see theory of logical types ). A property, being defined within one
variable or set is of ordinality one. A
relation between two entities is of ordinality two, ..., a relation with n arguments is of ordinality n. A different convention of expressing ordinality is to count: unary relation or property,
binary relation, ternary relation, quarternary relation,..., n-ary relation. A
system within n variables contains up to n!/(m!(n-m)!) relations of ordinality m, msee
structure, organization ). (
Krippendorff )
