So, I need to know whether the following is a function or not. "The mapping from any natural number $n$ to a set that only contains multiples of $n$."
Intuitively, this is a total function because the input will always produce a unique set. However, I'm confused because outputs are only meant to have one unique output, so would this not be a function because lots of different numbers are produced (all the numbers that are the multiples of $n$)
Could someone clarify whether it matters if multiple numbers are produced as the output?