<owl:ObjectProperty rdf:ID="connectsTo">
<rdf:type rdf:resource="http://www.w3.org/2002/07/owl#SymmetricProperty"/>
<rdfs:domain rdf:resource="#NaturallyOccurringWaterSource"/>
<rdfs:range rdf:resource="#NaturallyOccurringWaterSource"/>
</owl:ObjectProperty>
rdf(type,connectsTo,#SymmetricProperty).
rdf(type,domain,#NaturallyOccurringWaterSource).
rdf(type,range,#NaturallyOccurringWaterSource).
---- rdfs implicit rules ----
rdf(connectsTo,piritajogi,tallinnalaht) ... -> ...
rdf(type,piritajogi,#NaturallyOccurringWaterSource)
A x y u v (rdf(x,domain,y) & rdf(x,u,v) -> rdf(type,u,y))
---- owl implicit rules ---
rdf(connectsTo,piritajogi,tallinnalaht) ... -> ...
rdf(connectsTo,tallinnalaht,piritajogi)
A x u v ( rdf(x,type,#SymmetricProperty) &
rdf(x,u,v) -> rdf(x,v,u)).
flueve = river & all.emptiesinto(sea)
flueve(x) <-> [river(x) & A y (emptiesinto(x,y) -> sea(y))]