Answer:
0
Explanation:
ONE TO ONE FUNCTION : It is the function in which each element of the range of the function is connected with one element of the domain
Now let the set which contain 2 elements are m and the set which contain one element is n
For existence of one-to-one function there should be n\geq m . but here in m there are 2 elements and n there is 1 element so one-to-one function will not be defined
So 0 one-to-one function are formed