Title: Inverse function
Passage: Not all functions have inverse functions. In order for a function f: X → Y to have an inverse, it must have the property that for every y in Y there must be one, and only one x in X so that f(x) = y. This property ensures that a function g: Y → X will exist having the necessary relationship with f.
Question: if a function is not one to one does it have an inverse
Answer: no