\begin{slide}
\begin{itemize}
-\item L"osung: $m \neq 0 \longleftrightarrow \frac{\partial (\tanh (\beta Jm))}{\partial m} > 1$ bei $m=0$
-\item kritische Temperatur: $\frac{\partial (\tanh (\beta Jm))}{\partial m} = 1$ bei $m=0$
+\item L"osung: $m \neq 0 \longleftrightarrow \frac{\partial (\tanh (\beta Jm))}{\partial m} > 1$
+\item kritische Temperatur: $\frac{\partial (\tanh (\beta Jm))}{\partial m} = 1$ f"ur $m=0$
\end{itemize}
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% \begin{picture}(6,4)(-3,-2)
\[
\begin{array}{l}
\displaystyle \lambda_{\pm} = e^K \pm e^{-K} \\[2mm]
- \displaystyle Z = 2^N \cosh^N (K) + 2^N \sinh^N (K) = 2^N \cosh^N (K) (1 + \tanh^N (K)) \stackrel{N >> 1}{\longrightarrow} 2^N \cosh^N (K) \\[2mm]
+ \displaystyle Z = 2^N \cosh^N (K) + 2^N \sinh^N (K) \stackrel{N >> 1}{\longrightarrow} 2^N \cosh^N (K) \\[2mm]
\displaystyle F = -k_B T \, \textrm{ln} \, Z \stackrel{N >> 1}{\longrightarrow} -N k_B T \, \textrm{ln} \, (2 \cosh (\beta J))
\end{array}
\]