public static function isStandardArcrole( $role )
	{
		return in_array( $role, array(
			"http://www.w3.org/1999/xlink/properties/linkbase",
			self::$arcRoleConceptLabel,
			self::$arcRoleConceptReference,
			self::$arcRoleFactFootnote,
			self::$arcRoleParentChild,
			self::$arcRoleSummationItem,
			self::$arcRoleGeneralSpecial,
			self::$arcRoleEssenceAlias,
			self::$arcRoleSimilarTuples,
			self::$arcRoleRequiresElement,
		) );
	}