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Couple of fixes, simplify an exercise a bit
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jirilebl committed May 5, 2024
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6 changes: 3 additions & 3 deletions ca.tex
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Expand Up @@ -14594,7 +14594,7 @@ \subsection{Harnack's inequality}
\frac{1}{2\pi}
\int_{-\pi}^\pi f(p+Se^{it}) \, dt
\right)
\leq
=
\frac{S+r}{S-r}
f(p) .
\end{equation*}
Expand Down Expand Up @@ -14839,11 +14839,11 @@ \subsection{Harnack's principle}

\begin{exercise}
Prove a Montel-like theorem for harmonic functions. Suppose $U \subset \C$
is open and $\{ f_n \}$ is a sequence of nonnegative harmonic functions.
is a domain and $\{ f_n \}$ is a sequence of nonnegative harmonic functions.
Show that at least one (or both) of the following are true:
\begin{enumerate}[(i)]
\item
There exists a subsequence converging to $\infty$ uniformly on compact subsets.
There exists a subsequence converging to $+\infty$ uniformly on compact subsets.
\item
There exists a subsequence converging to a harmonic function
uniformly on compact subsets.
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5 changes: 5 additions & 0 deletions changes-draft.html
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Expand Up @@ -78,4 +78,9 @@
The way it was previously was only asking for the hard part (the if),
and so it wasn't giving a good parallel to the theorem.
The easy part is actually a good way to start the exercise anyway.
<li>On page 180, the last displayed inequality in the proof of Harnack is
actually an equality.
<li><b>Simplify Exercise 7.2.26 a little</b> by assuming that \(U\) is
connected to having to think about the technicality of countably many
components which is not really important.
<li>Clarify the proof of Rado's theorem.
8 changes: 4 additions & 4 deletions slides/7.2.3-7.2.4.tex
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Expand Up @@ -89,7 +89,7 @@
\int_{-\pi}^\pi f(p+Se^{it}) \, dt
\right)
\pause
\leq
=
\frac{S+r}{S-r}
\,
f(p) .
Expand Down Expand Up @@ -329,7 +329,7 @@
\medskip
\pause

Suppose $f(z) = \lim f_n(p) < +\infty$ for every $z \in U$.
Suppose $f(z) = \lim f_n(z) < +\infty$ for every $z \in U$.

\pause
Let $K \subset U$ be compact, take the $C$ from Harnack's, and take any $p \in K$.
Expand Down Expand Up @@ -382,11 +382,11 @@

\textbf{Exercise:}
Prove a Montel-like theorem for harmonic functions. Suppose $U \subset \C$
is open and $\{ f_n \}$ is a sequence of nonnegative harmonic functions.
is a domain and $\{ f_n \}$ is a sequence of nonnegative harmonic functions.
Show that at least one (or both) of the following are true:
\begin{enumerate}[(i)]
\item
$\exists$ a subsequence converging to $\infty$ uniformly on compact subsets.
$\exists$ a subsequence converging to $+\infty$ uniformly on compact subsets.
\item
$\exists$ a subsequence converging to a harmonic function
uniformly on compact subsets.
Expand Down

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