RULESET "examples of Jena3 rules"
PREFIX eg: <urn:x-hp-jena:jena-3-rules:examples>
    {
    RULE "if it has a number plate, it's a vehicle"
        { ?x eg:hasNumberPlate ?p } => { ?x a eg:Vehicle }

    RULE "collaborations have multiple (distinct) authors"
        { ?work eg:hasAuthor ?a, ?b FILTER (?a != ?b) } => { ?work a eg:Collaboration }

    RULE "count ancient collaborations as classics"
        { ?work a eg:Collaboration; eg:publicationDate ?d
        FILTER (years(?d) < years(today()) - 50)
        } => { ?work a eg:Classic }

    RULE "spot a problem: collaborations can't be vehicles"
        { ?x a eg:Collaboration, eg:Vehicle }
        => { ?x eg:hasProblem "oops: both Collaboration and Vehicle" }

    RULE "count the number of problematic items"
        { ALL ?item. {?item eg:hasProblem ?p} } 
        => { LET ?n = count(?item) [eg:problemCount ?n] }
    }