Let $X$ be a reflexive normed space, let $Q$ be the natural map from $X$ to $X^{**}$, and let $B_X,B_{X^{**}}$ denote the closed unit ball of $X$ and $X^{**}$. Then how to get $Q(B_X)=B_{X^{**}}$?
2026-05-15 23:26:07.1778887567
If a normed space $X$ is reflexive, then $Q(B_X)=B_{X^{**}}$.
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