public function getOperator()
    {
        $returnValue = null;

        
        if(empty($this->arithmeticOperator)){
        	$property = new core_kernel_classes_Property(RulesRdf::PROPERTY_OPERATION_OPERATOR);
        	$this->arithmeticOperator = $this->getUniquePropertyValue($property);
        }
        $returnValue = $this->arithmeticOperator;
        

        return $returnValue;
    }