Final answer:
The question seems to be about defining the universal set in mathematics, but it is incomplete as it does not provide details on what is included in 'U'.
Step-by-step explanation:
The given question appears to be incomplete as there is no continuation after 'U =' to define what the universal set includes. In mathematics, especially in the context of set theory, the universal set is the set that contains all objects under consideration for a particular discussion or problem. The universal set is typically represented by the symbol 'U' and varies depending on the context.
Without additional information, it is not possible to provide a specific answer about the contents of the universal set in question. Usually, the universal set may contain numbers, such as when discussing subsets of real numbers, or it could contain other mathematical objects like shapes or functions.
Defining the universal set enables comparisons between the universal set and its subsets and provides a reference for operations like union and intersection.