You will be given a definition of a task first, then some input of the task.
You will be given a passage, and your task is to generate a Yes/No question that is answerable based on the given passage.

In mathematics, and more specifically set theory, the empty set or null set is the unique set having no elements; its size or cardinality (count of elements in a set) is zero. Some axiomatic set theories ensure that the empty set exists by including an axiom of empty set; in other theories, its existence can be deduced. Many possible properties of sets are vacuously true for the empty set.
Output:
is an empty set an element of an empty set?