Algae Rules

RDFS semantics are implemented as rules:

...
# rdfs subClassOf and rdf type
fwrule ask (rdf::type ?a ?b.
            rdfs::subClassOf ?b ?c)
    assert (rdf::type ?a ?c)
# rdfs subClassOf transitivity
fwrule ask (rdfs::subClassOf ?a ?b.
            rdfs::subClassOf ?b ?c)
    assert (rdfs::subClassOf ?a ?c)
...

Could switch to OWL tiny-style transitivity.