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-rw-r--r--ictp-saifr_colloquium.tex29
1 files changed, 29 insertions, 0 deletions
diff --git a/ictp-saifr_colloquium.tex b/ictp-saifr_colloquium.tex
index 1d823a7..e1c78bb 100644
--- a/ictp-saifr_colloquium.tex
+++ b/ictp-saifr_colloquium.tex
@@ -863,6 +863,35 @@
\end{frame}
\begin{frame}
+ \frametitle{A simple model of nonlinear least squares}
+ \begin{columns}
+ \begin{column}{0.9\textwidth}
+ Data: $x_i\mapsto J^i$, $N\times\cdots\times N$ $p$-tensors of Gaussian random numbers\\
+ \hphantom{Data: }$y_i\mapsto V_0$, a constant \\
+
+ \medskip
+
+ Parameters: $\pmb a$ is an $N$-dimensional vector constrained to live on the sphere \\
+
+ \medskip
+
+ Model: $\hat f(J\mid\pmb a)$ is the homogeneous degree-$p$ polynomial
+ \[
+ \hat f(J\mid \pmb a)
+ =\sum_{i_1=1}^N\cdots\sum_{i_p=1}^NJ_{i_1,\ldots,i_p}a_{i_1}\cdots a_{i_p}
+ \]
+ Cost function: the usual
+ \[
+ \chi^2(\pmb a\mid J^1,\ldots,J^M)
+ =\sum_{i=1}^M\left[
+ V_0-\hat f(J^i\mid\pmb a)
+ \right]^2
+ \]
+ \end{column}
+ \end{columns}
+\end{frame}
+
+\begin{frame}
\frametitle{The Euler characteristic \boldmath{$\chi$}}
\begin{columns}
\begin{column}{0.5\textwidth}