Let A abcd and B 123 Determine whether the relation R from A

Let A= {a,b,c,d} and B= {1,2,3}. Determine whether the relation R from A to B is a function. R= {(a,3), (b,2), (c,1)}

Solution

A relation from a set X to a set Y is called a function if each element of X is related to exactly one element in Y. That is, given an element x in X, there is only one element in Y that x is related to.

Here, the element \'d\' in A is not related to any element in B. So, the relation is not a function.