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\section*{M-5710.  Assignment 4}
\subsection*{Due Monday, September 22}
Part 1. Min-max problem
\begin{itemize}
\item  Compute 
$$ I_{xy}=\min_x \max_y \left( \mbox{sign} \left( \frac{1}{x \, y} \right)\right)
$$
and 
$$ I_{yx} =\max_y \min_x \left( \mbox{sign} \left( \frac{1}{x \, y}
 \right)\right)
$$
and compare them. 

\item Compute 
$$ I_{xy}^S=\min_x \max_y  \left(\mbox{sign} \left( x\, y \right)\right)
$$
and 
$$ I_{yx}^S =\max_y \min_x   \left(\mbox{sign} \left( {x \, y} \right)\right)
$$
and compare them. 

\item Comment on the difference between these two cases.


\item Find another example of a function $f(x, y)$ for which  
minimax is not equal to maximin. 
\end{itemize}
Part 2.
Strang: 2.2.3, 2.2.4, 2.2.13 (Used notations are introduces in Section 2.2)

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