Theory:

Let us first consider the representation given below.
 
9 (1).png
 
The image given above is a cipher circle. Here \(A \rightarrow D\), \(B \rightarrow E\), and so on.
 
When represented as a function, the cipher circle is both one - one and onto.
 
Bijection:
A function that in both one - one and onto is a bijection.
1.png
 
Since the bijection function is one - one and onto, it is also called one - one correspondence.
 
Also, a bijective function is both surjective and injective.