Question:
Write down all possible subsets of each of the following sets:
(i) $\{a\}$,
(ii) $\{0,1\}$,
(iii) $\{a, b, c\}$,
(iv) $\{1,\{1\}\}$
(v) $\{\phi\}$.
Solution:
(i) $\phi,\{a\}$
(ii) $\phi,\{0\},\{1\},\{0,1\}$
(iii) $\phi,\{\mathrm{a}\},\{\mathrm{b}\},\{\mathrm{c}\},\{\mathrm{a}, \mathrm{b}\},\{\mathrm{b}, \mathrm{c}\},\{\mathrm{a}, \mathrm{c}\},\{\mathrm{a}, \mathrm{b}, \mathrm{c}\}$
(iv) $\phi,\{1\},\{\{1\}\},\{1,\{1\}\}$
(v) $\phi,\{\phi\}$