Standard OIL

Standard OIL extends OIL-Lite with the possibility to define instances of classes and roles. These definitions are of the form (instance-of $i$ $C_1,\ldots,C_n$) and (related $S$ $i$ $j$), where $C$ (possibly subscripted) is a class expression, $S$ is a slot name and $i$ and $j$ are individual names. An axiom (instance-of $i$ $C_1,\ldots,C_n$) is equivalent to (instance-of $i$ ( $C_1~\key{and}~\ldots~\key{and}~C_n$). These axioms are simply treated as ``syntactic sugar'' for axioms of the form

covered-by (one-of $i$) $C$

(i.e., $P_i \sqsubseteq C$), and

covered-by (one-of $i$) (slot-constraint $S$ has-value (one-of j))

(i.e., $P_i \sqsubseteq \ensuremath{\exists S . P_j}$) respectively.