Analysis Services 2008 $SYSTEM.DBSCHEMA_% DMVs
In Analysis Services 2008 there are 4 DBSCHEMA Dynamic Management Views (DMVs):
$SYSTEM.DBSCHEMA_CATALOGS
$SYSTEM.DBSCHEMA_COLUMNS
$SYSTEM.DBSCHEMA_PROVIDER_TYPES
$SYSTEM.DBSCHEMA_TABLES
These DMVs describe database schema that was used to build SSAS database.
Here is a diagram that I got after exporting structure of above DMVs into SQL Server database: