Document (
 Prefix(ex <http://example.org/example#>)
 Prefix(xs <http://www.w3.org/2001/XMLSchema#>) 

 Group ( 

  Forall ?Customer (
     ex:discount(?Customer 10) :- ex:gold(?Customer)
  )

  Forall ?Customer (
     ex:discount(?Customer 5) :- ex:silver(?Customer)
  )

  ex:gold("John Doe")
 )
)