ResultSet
result variable: a
result variable: z
result variable: d
size: 2
solution: ResultSolution
  binding: ResultBinding
    variable: a
    value: s1
  binding: ResultBinding
    variable: z
    value: s2
  binding: ResultBinding
    variable: d
    value: Value
solution: ResultSolution
  binding: ResultBinding
    variable: a
    value: http://rdf.hp.com/r
  binding: ResultBinding
    variable: z
    value: http://rdf.hp.com/r
  binding: ResultBinding
    variable: d
    value: http://rdf.hp.com/r