Function as Mapping Math Example 2

Solution

1. 1
   Check whether each domain element has exactly one output: $1 \mapsto 2$ and $1 \mapsto 3$.
2. 2
   The element $1$ is mapped to two different values ($2$ and $3$). This violates the definition of a function.
3. 3
   For $R$ to be a function, each input must have a unique output. Since input $1$ has two outputs, $R$ is a relation but not a function.