The previous upper and lower bound values are not defined. Specifying them in the brackets is odd and confusing. These values could be anything, so either specify the original carfdinality for the category somewhere and then reference to it, or remove the bounds in the brackets.

Existing Wording:

Require at least one category without changing its upper bound :

Allow at most one category without changing its lower bound (0):

Proposed Wording:

Require at least one category without changing its upper bound:

Allow at most one category without changing its lower bound: