unordered pair
Deductions
- unordered pair is subclass of collective entity ⇐ (unordered pair is subclass of dyad), (dyad is subclass of collective entity), (is subclass of is a transitive relation)
- unordered pair is subclass of entity ⇐ (unordered pair is subclass of dyad), (dyad is subclass of entity), (is subclass of is a transitive relation)