Alegebra- Function or NOT a function

Question

if you have a relation with the domains: 0,1,2,3,4 and a range of: 3,1,2,4,2 does this mean it is not a function because there are two outputs of the number 2? Or can it only not be function if there are two of the same inputs with a different output?

Answer 1

A function can be described as a cartesian product of the domain and the range, so the relation you describe is a function. You are correct when saying that a function can't have an input with two different outputs