@prefix xsd:     <http://www.w3.org/2001/XMLSchema#> .
@prefix rs:      <http://www.w3.org/2001/sw/DataAccess/tests/result-set#> .
@prefix rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix :        <http://example.org/things#> .

[]    rdf:type    rs:ResultSet ;
      rs:resultVariable  "x" ;
      rs:resultVariable  "v" ;
      rs:solution
                  [ rs:binding  [ rs:value    :xb ;
                                  rs:variable  "x"
                                ] ;
                    rs:binding  [ rs:value    [] ;
                                  rs:variable  "v"
                                ]
                  ] .