Determine whether or not each definition * given below gives a binary operation. In the event that * is not a binary operation give justification of this. On Z + , defined * by a*b = a – b Here, Z + denotes the set of all non – negative integers.

Question

Philoid · Accepted Answer

Given that ‘*’ is an operation that is valid in the Positive integers ‘Z ⁺ ’ and it is defined as given:

⇒ a*b = a – b, where a,b∈Z ⁺

Since a∈Z ⁺ and b∈Z ⁺ ,

According to the problem it is given that on applying the operation ‘*’ for two given positive integers it gives a positive integer as a result of the operation,

⇒ a*b∈Z ⁺ ...... (1)

Let us take the values a = 1 and b = 2

⇒ a – b = 1 – 2

⇒ a – b = – 1∉Z ⁺

∴ The operation * does not define a binary operation on Z ⁺

Determine whether or not each definition * given below gives a binary operation. In the event that * is not a binary operation give justification of this.On Z + , defined * by a*b = a – bHere, Z + denotes the set of all non – negative integers.

Determine whether or not each definition * given below gives a binary operation. In the event that * is not a binary operation give justification of this.
On Z ⁺ , defined * by a*b = a – b

Here, Z ⁺ denotes the set of all non – negative integers.