Normally all predicates are considered as relations in knowledge representation. Predicates can be monadic, diadic or n-adic. Presently GNOWSYS supports only diadic relations. Monadic relations are added directly on objects as attributes.
A relation is usually a proposition. GNOWSYS will support quantifiers (all, some, none, n etc.) while adding the relations. Each relation when added must be a WFF (well formed formula).