RDF Query Model Query Model - SPARQL Protocol and RDF Query Language Given U (set of URIs), L (set of literals), and V (set of variables), a SPARQL expression is de???ned recursively: an atomic triple pattern, which is an element of (U ??? V ) ?? (U ??? V ) ?? (U ??? V ??? L) ?x hasName ???Abraham Lincoln??? P FILTER R, where P is a graph pattern expression and R is a built-in SPARQL condition (i.