Uniformly convex Banach space
= Uniformly convex Banach space
A Banach space $X$ is uniformly convex when, for every $\varepsilon>0$, some $\delta>0$ satisfies
$$
\lVert x\rVert,\lVert y\rVert\leq1,
\quad \lVert x-y\rVert\geq\varepsilon
\quad\Longrightarrow\quad
\left\lVert\frac{x+y}{2}\right\rVert\leq1-\delta.
$$
This is a complete <uniformly convex space>.