mdx - "DESCENDANTS" と "0, LEAVES" とはどういう意味ですか?

Question

次の MDX クエリがあります。

select {[Measures].[Internet Sales Amount]} on axis(0), 
DESCENDANTS({[Customer].[Education].[All Customers].[Bachelors],
             [Customer].[Education].[All Customers].[Graduate Degree]},0,LEAVES) on axis(1) ,
DESCENDANTS({[Geography].[Country].[All Geographies].[Australia],
         [Geography].[Country].[All Geographies].[Canada],
         [Geography].[Country].[All Geographies].[France]},0,LEAVES) on axis(2) 
from [Adventure Works]

DESCENDANTSとはどういう0, LEAVES意味ですか?