Write down all possible subsets of each of the following sets :
(i) {a} (ii) {0, 1}
(iii) {a, b, c} (iv) {1, {1}}
(v) {ϕ}
(i) We know that , if a set has n eleents, then its power set has 2n elements. Hence, n= 1, so there 21=2 subsets of the given set. The possible subsets are ϕ, {a}.
(ii) The set has two elements, so power set has 22=4 elements, namely ϕ, {0}, {1}, {0, 1}.
(iii) The set has 3 elements, so power set has 23=8 elements, namely ϕ, {a}, {b}, {c}, {a, b}, {b, c}, {a, c}, {a, b, c}.
(iv) The set has 2 elements, so power set 22=4 elements, namely ϕ,{1}, {{1}}, {1, {1}}.
(v) The set has element, so power set has 21=2 elements, namely ϕ, {ϕ}.