LNum Element (XMLA)
For HierarchyInfo elements, the LNum element contains the name of the property that provides the level ordinal positions of the hierarchy. The value is equivalent to the LEVEL_NUMBER property defined for axis rowsets in the OLE DB for OLAP specification.
For Member elements, the LNum element contains the zero-based ordinal position, from the root level of the hierarchy, of the member represented by the parent Member element. A value of zero represents the root level of the hierarchy.