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.
(iv) On Z+, defined a∗b=|a−b|
On Z+, defined a∗b=|a−b|
It is seen that for each a,b, ∈Z+, there is a unique element |a−b| in Z+.
This means that ∗ carries each pair (a,b)to a unique element a∗b=|a−b| in Z+. Therefore, ∗ is a binary operation.