quddusaliquddus said:Sorry. But I can't seem to locate it in their webpage.
A set in set theory is a collection of distinct objects, usually denoted by curly braces, such as {1,2,3}. These objects can be any type of mathematical entity, including numbers, letters, or even other sets.
A subset is a set that contains only elements that are also in another set. In other words, every element in the subset is also in the larger set. For example, {1,2} is a subset of {1,2,3}, but {4,5} is not a subset of {1,2,3}.
The cardinality of a set is the number of elements it contains. For example, the cardinality of the set {1,2,3} is 3. If a set contains an infinite number of elements, its cardinality is denoted by the symbol ℝ (aleph-null).
An empty set is a set that contains no elements, denoted by ∅ or {}. A null set, on the other hand, is a set that has no defined elements. It is often used to represent a set that has not yet been defined or has no elements that satisfy a certain condition.
The power set of a set is the set of all possible subsets of that set, including the empty set and the set itself. For example, the power set of the set {1,2} is {{},{1},{2},{1,2}}. The cardinality of a power set with n elements is 2^n.