Subsets [ml={1,2,..,n} Power set:2lml ={SS C [n]} 2= A not-so-combinatorial proof: Let f(u)=2iml f(n)=2f(n-1)Subsets A not-so-combinatorial proof: Let f(n)=2f(n ￾ 1) [n] = {1, 2,...,n} ￾ ￾ ￾ 2[n] ￾ ￾ ￾ = f(n) = ￾ ￾ ￾ 2[n] ￾ ￾ ￾ 2[n] Power set: = {S | S ✓ [n]}