Bidual space
$\textbf{Bidual space}$
Let $X$ be a normed space. The bidual space of $X$ is the dual space $(X^*)^*$ of $X^*$ and is denoted by $X^{**}$.
𝐁𝐢𝐝𝐮𝐚𝐥 𝐬𝐩𝐚𝐜𝐞
Let 𝑋 be a normed space. The bidual space of 𝑋 is the dual space (𝑋*)* of 𝑋* and is denoted by 𝑋**.