Given $X=\{1,2,3,4,5,6\}$ and the sets on X: $A_1=\{\{1,2,3\},\{2,3,4,5\},\{1,6\}\}$ and $A_2=\{\{1,4,5\},\{2,3,6\},\{4,5,6\}\}$, show that $\sigma(A_1)=\sigma(A_2)$ without finding the $\sigma(A_1)$ and $\sigma(A_2)$?
I feel quite lost on this question, as I cannot think of any way of showing this, without finding the $\sigma$-algebra of both sets on X?
Any help will be greatly appreciated.