What is an example of a Banach space that is not a BK spaceBK-space?
A normnormed sequence space $X$ (with projections $p_n$) is a BK Space, if $X$ is Banach space and for all natural numbers n$n$, $p_n(\bar{x}) = x_n$ is continuous, for all $\bar{x}$ in X$X$.