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.
On Z+, define ∗ by a ∗ b = ab
It is given that on Z+, define ∗ by a ∗ b = ab
We can see that for each a, b ϵ Z+, there is a unique element ab in Z+.
⇒ * carries each pair (a, b) to a unique element a * b = ab in Z+.
Therefore, * is a binary operation.