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Blank Node Graphs - BNG
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BNG supports reasoning with forward rules described in RDF as

    _:bng_1 log:implies _:bng_2.

    _:bng_1 {
        RDF triples
    }

    _:bng_2 {
        RDF triples
    }

BNG supports reasoning with backward rules described in RDF as

    _:bng_1 log:isImpliedBy _:bng_2.

    _:bng_1 {
        RDF triple
    }

    _:bng_2 {
        RDF triples
    }

BNG supports querying with queries described in RDF as

    _:bng_1 log:query _:bng_2.

    _:bng_1 {
        RDF triples
    }

    _:bng_2 {
        RDF triples
    }

The var: prefix is <http://www.w3.org/2000/10/swap/var#> and is used for
variables that are interpreted as universally quantified variables except for
forward rule conclusion-only variables which are interpreted existentially.

Literal subjects are described as

    [] rdf:value "aha"; :p :o.
