code: private PExp getImpliesExists(ASetCompSetExp exp, ILexNameToken finmap,
  			ILexNameToken findex)
  	{
  		AExistsExp exists = new AExistsExp();
  
  		AMapDomainUnaryExp domExp = new AMapDomainUnaryExp();
  		domExp.setType(new ABooleanBasicType());
  		domExp.setExp(getVarExp(finmap));
  		List<PMultipleBind> bindList = getMultipleSetBindList(domExp, findex);
  		exists.setBindList(bindList);
  
  		exists.setPredicate(getExistsPredicate(exp, finmap, findex));
  		return exists;
  	}
docs: exists idx in set dom m & m(idx) =f(a)