1.3.6 Special Sets

Certain sets are of particular significance and are referred to as special sets. The two key special sets frequently used in defining and calculating probabilities are the empty set and the universal set.

An empty set is a set that contains no elements, denoted by the symbol of a slashed zero  or { }. It's a subset of every set i.e. If  is set, then  ⊂ . The cardinality of an empty set is 0, signifying that there are no elements within it.