fundamental

☼ Equivalent  Sets  :   Two sets  A  and  B  are said to be equivalent if  n (A)  =  n (B).

■ Remark  :   Equivalent sets are not always equal but equal sets are always equivalent. Thus,  { 10, 20…

☼ Equal  Sets  :   Two sets  A  and  B  are said to be equal, if each and every element of  A is in B and each and every element of  B is in A.

In this case we can write,  A  =  B….

☼  Finite  &  Infinite  Sets  :   A set in which the process of  counting of  elements surely comes to an end or one can take an upper limit for that set, is called a finite set

A set which is not finite is known as an infinit…

☼ Empty Set  :   A set containing no elements at all is called an empty set or a null set or a void set and it is denoted by . In property method,    =  { }.

 e.g. (i) {  x / x