A function is called a *one-to-one* function if it satisfies

whenever

The above condition becomes equivalent to the following:
``
always implies .''
When a function is a one-to-one function,
the
if and only if

We denote the inverse function of by the symbol .
**Domain of .**
If is a one-to-one function from the domain to the range ,
then the inverse function becomes a one-to-one function
from the domain to the range .

Department of Mathematics