👉 In mathematics, "properness" is a property that describes whether an object or quantity is considered to be part of a set. This means that it must belong to one of the elements in the set and not be excluded from being a member. For example, consider the set {1, 2, 3}. In this set, there are three elements: 1, 2, and 3. Since 4 is not an element of the set (it does not belong to
