# SPARQL FILTER test by value.
# Only one valus is known to be "a"^^t:type1
# (others maybe but the processor does not positively know this)

PREFIX  :       <http://example/ns#>
PREFIX  t:      <http://example/t#>

SELECT *
{ ?x :p ?v 
  FILTER ( ?v = "a"^^t:type1 )
}