You can use the name of the categorized column but you have to set following properties for this column:
It's important that it is not sorted and has marked "multiple values as separate entries".
EDIT:
It does work only for views with one category.
If you have the need to categorize more then one value then you have to concatenate them with "\" in one categorized column.
Example:
Given a document with multivalue fields
Field A: aaa, bbb, ccc
Field B: 111, 222
you would use a formula for categorized column
(A + "\\") *+ B
and name the categorized column in last property tab "column1"
put then the value "column1" in the unsorted multivalue column
then you'll get this view as result
You are then free to manipulate the value in second column with formula.