Let f X Y be a functionTrue or FalseA sufficient condition f

Let f: X Y be a function.True or False?A sufficient condition for f to be one-to-one is that for all elements y in Ym there is at most one x in X with f(x)= y.

Solution

true.

A function f from X to Y is called one-to-one (or 1-1) if whenever
f (x) = f (y) then x = y.  

No element of Y is the image of more than one element in X.

that is one-one function has an inverse that is also a function.