For example, the bit string \(11001\) represents the subset \(\{1,2,5\}\) since the first, second and fifth bits are 1's. The subset \(\{3,5\}\) would be coded by the string \(00101\text{.}\) What we really have here is a bijection from \(\pow(A)\) to \(\B^5\text{.}\)
in-context