Answer:
Step-by-step explanation:
The definition of a function f from A to B, regardless to injectivity or surjectivity, is that the domain of f is A, in its entirety.
This means that if f:AâB, then for every aâA, there is a unique bâB such that the pair (a,b)âf.
So the converse holds just for it to be a function from A to B.