Let A = { $\displaystyle ( x_{n} ) : \sum_{n=1}^{\infty} | x_{n} | \leq 1$ } Find the interior and the closure of A in $\displaystyle c_{0} $. Here $\displaystyle c_{0} = $ { $\displaystyle (x_{n}) \in R : x_{n} -> 0 $ } i.e space of all sequences that converges to 0.

Can anyone help, any hint is appreciated. (Thinking)