\item \emph{Show that it is impossible to deliver food packages in such a
way that each of the villages consumes one food package per time unit
forever.}
+ Incrementally increasing the number of iterations does not result in a
+ state where a city is without food. Therefore we try to find proof that
+ the truck is actually capable of keeping all cities saturated.
- \item \emph{Show that this is possible if the capacity of the truck is
- increased to 320 food packages. (Note that a finite graph contains an
- infinite path starting in a node $v$ if and only if there is a path
- from $v$ to a node $w$ for which there is a non-empty path from $w$ to
- itself.)}
To show this we need to prove that there is a state in the statespace
that is exactly the same as some previous state. To do this we add the
following formula to the conjunction.
When we incrementally increase the number of iterations we see that
when we have more then $8$ iterations we encounter a cycle. This is
shown in the following table where iteration $2$ and iteration $9$ are
- equal.
+ equal. The amount dumped is only shown for more readability. For state
+ isomorphism it is not a factor.
\begin{table}[H]
\centering
- \begin{tabular}{ccccccc}
+ \begin{tabular}{lrrrrcr}
\toprule
$I$ & $A$ & $B$ & $C$ & Truck & Location & Dump\\
\midrule
- $0$ & $40$ & $30$ & $145$ & $320$ & $0$ & $0$\\
- $1$ & $19$ & $22$ & $124$ & $307$ & $2$ & $9$\\
- $2$ & $96$ & $5$ & $107$ & $213$ & $1$ & $98$\\
- $3$ & $79$ & $119$ & $90$ & $82$ & $2$ & $133$\\
- $4$ & $58$ & $98$ & $69$ & $320$ & $0$ & $0$\\
- $5$ & $108$ & $69$ & $40$ & $241$ & $1$ & $79$\\
- $6$ & $76$ & $37$ & $194$ & $55$ & $3$ & $186$\\
- $7$ & $39$ & $55$ & $157$ & $0$ & $2$ & $53$\\
- $8$ & $18$ & $34$ & $136$ & $320$ & $0$ & $0$\\
- $9$ & $96$ & $5$ & $107$ & $213$ & $1$ & $107$\\
+ $0$ & $40$ & $30$ & $145$ & $300$ & $S$ & $0$\\
+ $1$ & $19$ & $36$ & $124$ & $273$ & $B$ & $27$\\
+ \textbf{2} & \textbf{120} & \textbf{19} & \textbf{107} &
+ \textbf{155} & \textbf{A} & \textbf{118}\\
+ $3$ & $103$ & $117$ & $90$ & $40$ & $B$ & $115$\\
+ $4$ & $82$ & $96$ & $69$ & $300$ & $S$ & $0$\\
+ $5$ & $94$ & $67$ & $40$ & $259$ & $A$ & $41$\\
+ $6$ & $62$ & $35$ & $194$ & $73$ & $C$ & $186$\\
+ $7$ & $25$ & $69$ & $157$ & $2$ & $B$ & $71$\\
+ $8$ & $4$ & $48$ & $136$ & $300$ & $S$ & $0$\\
+ \textbf{9} & \textbf{120} & \textbf{19} & \textbf{107} &
+ \textbf{155} & \textbf{A} & \textbf{145}\\
\bottomrule
\end{tabular}
\end{table}
+ \item \emph{Show that this is possible if the capacity of the truck is
+ increased to 320 food packages. (Note that a finite graph contains an
+ infinite path starting in a node $v$ if and only if there is a path
+ from $v$ to a node $w$ for which there is a non-empty path from $w$ to
+ itself.)}
+ Solution idem to $a.$. Just imagine the truck operator glueing $20$
+ food packages to the truck which he can not deliver.
\item \emph{Figure out whether it is possible if the capacity of the truck
is set to $318$.}
+ Solution idem to $a.$. Just imagine the truck operator glueing $18$
+ food packages to the truck which he can not deliver.
\end{enumerate}