Recently, I have seen the so-called uniform boundedness theorem, which says: > Let $(X,∥⋅∥)$ be a Banach space and $(Y,∥⋅∥)$ be a normed linear space. Let $A⊂B(X,Y)$ be a pointwise bounded family of bounded linear transformations from $X$ to $Y$ . Then the family $A$ is uniformly bounded. I was wondering if there is any 'simple' non-Banach space that verifies this property: that is, that **for all** choices of $Y$, a pointwise bounded family of bounded linear transformations is uniformly bounded. I have thought that maybe some kind of sequence space might work, but I have not quite found one that does.