std::decay related question

[Eric Lemings]

 
Page 490, section 20.3.1.2, paragraph 1 in the latest draft says this:
 
"Let Ui be decay<Ti>::type for each Ti in Types. Then each Vi in VTypes
is X& if Ui equals reference_wrapper<X>,
otherwise Vi is Ui."
 
What do you suppose the relationship is between type `X' and types `Ti'
and `Ui'?  I see how the latter two types are deduced from the type list
`Types' but not so sure about how type `X' is deduced from `Types'.
 
Brad.