private UnconditionalValueDerefSet duplicateFact(UnconditionalValueDerefSet fact){
  UnconditionalValueDerefSet copyOfFact=createFact();
  copy(fact,copyOfFact);
  fact=copyOfFact;
  return fact;
}

private UnconditionalValueDerefSet duplicateFact ( UnconditionalValueDerefSet fact ) { UnconditionalValueDerefSet copyOfFact = createFact ( ) ; copy ( fact , copyOfFact ) ; fact = copyOfFact ; return fact ; }
return a duplicate of given dataflow fact .
