What is included in a set in set theory terms?

In set theory, a set is a collection of distinct elements considered as a whole. The components of a set include:

• Elements (members) of the set: objects that belong to this set.
• Lack of order: the elements of a set are unordered.
• Uniqueness: each element appears in the set no more than once (no repetitions).

For example, the set A = {1, 2, 3} consists of three elements: 1, 2, and 3. The order of their listing does not matter, and each element is unique.