Minor housekeeping.

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Bokuan Li
2026-06-27 14:12:40 -04:00
parent 968fbe6eba
commit 3d9c47bda1
2 changed files with 17 additions and 1 deletions

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@@ -66,3 +66,19 @@
On the other hand, let $\mathcal{T} \subset 2^E$ be a locally convex topology consistent with $\dpn{E, F}{\lambda}$. By the \hyperref[Banach-Alaoglu Theorem]{theorem:alaoglu}, every $\mathcal{T}$-equicontinuous set is relatively $\sigma(F, E)$-compact. Therefore $\mathcal{T}$ is coarser than the topology of uniform convergence on relatively $\sigma(E, F)$-compact, convex, and circled sets.
\end{proof}
\begin{definition}[Mackey Space]
\label{definition:mackey-space}
Let $E$ be a separated locally convex space over $K \in \RC$, then $E$ is a \textbf{Mackey space} if $E$ is equipped with the Mackey topology of $\dpn{E, E^*}{E}$.
\end{definition}
\begin{proposition}
\label{proposition:barreled-mackey}
Let $E$ be a separated barreled space over $K \in \RC$, then $E$ is a Mackey space.
\end{proposition}
\begin{proof}
Let $\cf \subset E^*$ be a $\sigma(E^*, E)$-compact set and $U \in \cn_{K}(0)$ be a barrel, then $V = \bigcap_{\phi \in \cf}\phi^{-1}(U)$ is convex, circled, and closed. For each $x \in E$, $\cf(x) = \bracs{\dpn{x, \phi}{E}|\phi \in \cf}$ is bounded. Thus $V$ is absorbing and hence a barrel. Since $E$ is barreled, $V \in \cn_E(0)$. Therefore the Mackey topology is contained in the topology of $E$, and $E$ is a Mackey space.
\end{proof}