Question -
Answer -
Let f ={(x, y): x is a person, y is the mother of x}
As, for eachelement x in domain set, there is a unique relatedelement y in co-domain set.
So, f is thefunction.
Injection test:
As, y can be mother of two or more persons
So, f is not injective.
Surjection test:
For everymother y defined by (x, y), there exists aperson x for whom y is mother.
So, f is surjective.
Therefore, f is surjective function.
(ii) Let g ={(a, b): a is a person, b is an ancestor of a}
Since, the ordered map (a, b) does not map ‘a’ – a person to a livingperson.
So, g is not a function.