1.4 Subsets and Power Sets

Let the elements be $x = \phi$ and $y = 1$. So $A = \{x, y\}$. Subsets are:

1. $\phi$ (Null set)
2. $\{x\} = \{\phi\}$ (Singleton set containing empty set)
3. $\{y\} = \{1\}$
4. $\{x, y\} = \{\phi, 1\} = A$

Total subsets: $2^2 = 4$.