BK-space

Summary

A BK-space is a sequence space with a norm that makes it a Banach space in which each coordinate $x \mapsto x_n$ is continuous. The letters stand for Banach and the German word Koordinate. BK-spaces are exactly the FK-spaces whose topology comes from a norm. The spaces $\ell^p$, $c$ and $c_0$ with their usual norms are the basic examples.