Set class-5
Empty Set The set is empty! This means that there are no elements in the set. This set is represented by ϕ (read as phi) or {}. An empty set is hence defined as: Definition: If a set doesn’t have any elements, it is known as an empty set or null set or void set. For e.g. consider the set, P = {x : x is a leap year between 1904 and 1908} Between 1904 and 1908, there is no leap year. So, P = ϕ. Notes,p= {x:x read as x such that x} . Singleton Set If a set contains only one element, then it is called a singleton set. For e.g. A = {x : x is an even prime number} B = {y : y is a whole number which is not a natural number} Finite Set In this set, the number of elements is finite. All the empty sets also fall into the category of finite sets. Definition: If a set contains no element or a definite number of elements, it is called a finite set. If the set is non-empty, it is called a non-empty finite set. Some examples of finite sets are: ...