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@ -199,8 +199,8 @@
\[
D \subseteq \N^\N \mathbin{\text{\reflectbox{$\coloneqq$}}} \cN
\]
and a continuous bijection $f\colon D \to X$
(the inverse does not need to be continuous).
and a continuous bijection from
$D$ onto $X$ (the inverse does not need to be continuous).
Moreover there is a continuous surjection $g: \cN \to X$
extending $f$.

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@ -64,7 +64,7 @@
Take $S \coloneqq \{s \in \N^{<\N}: \exists x \in D, n \in \N.~x\defon{n} = s\}$.
Clearly $S$ is a pruned tree.
Moreover, since $D$ is closed, we have that\footnote{cf.~\yaref{s3e1}}
Moreover, since $D$ is closed, we have that (cf.~\yaref{s3e1})
\[
D = [S] = \{x \in \N^\N : \forall n \in \N.~x\defon{n} \in S\}.
\]

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@ -1,4 +1,5 @@
\subsection{The Ellis semigroup}
% TODO ANKI-MARKER
\lecture{17}{2023-12-12}{The Ellis semigroup}
Let $(X, d)$ be a compact metric space
@ -74,7 +75,7 @@ Properties of $(X,T)$ translate to properties of $E(X,T)$:
\]
\end{claim}
\begin{subproof}
Cf.~\yaref{s11e1}
\todo{Homework}
\end{subproof}
Let $g \in G$.
@ -162,8 +163,6 @@ But it is interesting for other semigroups.
\todo{The other direction is left as an easy exercise.}
\end{proof}
% TODO ANKI-MARKER
Let $(X,T)$ be a flow.
Then by Zorn's lemma, there exists $X_0 \subseteq X$
such that $(X_0, T)$ is minimal.