sir,suppose set A={1,2,3} and given set {0,1}!!
acc to condition 1,2 from set A can be mapped to 1 because they said +ve no less n but only one at a time from SET A... means if 2 from set A mapped to 1 in set {0,1} than reamaining elements from SET A ie 1,3 will be mapped to zero... so total we should get only 2 functions from this example..
how 2(n-1).??