Theory of Sets

A set is  a collection of well  defined objects. The objects of a set are
called elements or members of the set. A set is denoted by the capital letters.
  Example:
           The collection of jewels
   in your home.


Cardinal Number:

            The number of elements in a set "A"  is called the cardinal number of a set and it is denoted by n(A).

Different kinds of sets:

The empty set:

        A set which containing no elements is called the empty set
 or null set or void set.
          The cardinal number of the empty set is zero.

    Finite set:

             If the number of elements in a set is zero or finite,then the set is called a finite set.    
              The cardinal number of a finite set is finite.







Infinite set:

              A set is said to be an infinite set if the number of elements in a set is infinite.

                          The cardinal number of a infinite set is not a finite number.



Singleton set:

          A set containing only one element is called a singleton set.

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