public function exposeCategory(RdfProperty $property, $value)
    {
        $exposeProperty = new RdfProperty(self::EXPOSE_PROP_URI);

        if ($value == true) {
            $property->setPropertyValue($exposeProperty, GenerisRdf::GENERIS_TRUE);
        } else {
            $property->removePropertyValue($exposeProperty, GenerisRdf::GENERIS_TRUE);
        }
    }