(1) __Union of Sets:__**The union of two sets A and B is the set of all the elements which are either in A or in B or in both A and B**. It is denoted by .

Let

(2) __Intersection of Sets:__**The intersection of two sets A and B is the set of all the elements which are common to both A and B**. It is denoted by

Let

(3) __Difference of Two Sets:__** is the set of all those elements of A which are not elements of B. **

Similarly, is the set of all those elements of B which are not elements of A.

Let and

Then,

(4) ** Symmetric Difference of Two Sets:** Let A and B be two sets. is the symmetric difference between two sets. It is denoted by .

Consider and

Then,

(5) ** Complement of a set: The complement of a set A is the set of all those elements of the universal set U which are not element of A**. It is denoted by or or .

Let

Then,

__RESULTS ON COMPLEMENT__