Determine whether or not each of the definition of ∗ given below gives a binary operation. In the event that ∗ is not a binary operation, give justification for this.
(v) On Z+, defined ∗ by a∗b=a
On Z+, defined ∗ by a∗b=a
It is seen that for each a,b∈Z+, there is a unique element a∈Z+.
This means that ∗ carries each pair (a,b) to a unique element a∗b =a in Z+.
Therefore, ∗ is a binary operation.