Added counter examples to the open mapping theorem.

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Bokuan Li
2026-10-02 15:38:20 -04:00
parent 1bd178d7b3
commit 8857bb9fd9
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@@ -150,3 +150,13 @@
\end{proof}
\begin{example}
\label{example:open-mapping-counters}
Let $E = l^1(\natp; \complex)$ and $F$ be $l^1(\natp; \complex)$ equipped with the uniform norm, then the identity $E \to F$ is continuous but not open.
Let $E = C^1([0, 1]; \complex)$ equipped with the uniform norm, $F = C([0, 1]; \complex)$, and $D: E \to F$ be the differentiation operator, then $D$ has closed graph, but is not continuous.
\end{example}