diff --git a/eulerg/eulerg.tex b/eulerg/eulerg.tex index 04b9ca6..94dc128 100644 --- a/eulerg/eulerg.tex +++ b/eulerg/eulerg.tex @@ -104,9 +104,11 @@ $$ D \cap E \neq \emptyset $$ Clearly though these intersections are different, because in the $A$, $B$ case -$$ A \backslash B = \emptyset \wedge B \backslash A \neq \emptyset $$ +$ A \backslash B = \emptyset \wedge B \backslash A \neq \emptyset $ This is not the case for $D$, $E$ where: -$$ D \backslash E \neq \emptyset \wedge E \backslash D \neq \emptyset $$ +$ D \backslash E \neq \emptyset \wedge E \backslash D \neq \emptyset $. +Another way of expressing this is that $A \cap B \neq \emptyset$ and +$ D \subset E$. \paragraph{Enclosure} To distinguish between these we can term the $A$, $B$ case to be @@ -194,15 +196,17 @@ Figure \ref{fig:eulerg_pic} shows a {\pic} consisting of contours $M,N,O,P$ and \label{fig:eulerg_pic} \end{figure} -\textbf{rule:} +%\textbf{rule:} \begin{definition} If any contour in a {\pic} is enclosed by any contour not belonging to the chain, all the countours within the -{\pic} will be enclosed by it. This is because a contour -enclosing which bisects(????) another contour in a {\pic} -becomes part of the pure~intersection~chain. Hmmmm thats true but a better way to say it ???? +{\pic} will be enclosed by it. \end{definition} +This is because a contour +enclosing which bisects another contour in a {\pic} +becomes part of the pure~intersection~chain. +% Hmmmm thats true but a better way to say it ???? %The diagram in figure \ref{fig:eulerg_enc} can be represented by the following relationships. @@ -284,9 +288,8 @@ see figure \ref{fig:eulerg_pic_g_a_unc}. \end{figure} -\pagebreak[4] -\section{reduction of searches for available zones} - +\pagebreak[0] +\section{Reduction of searches for available zones} Another property of any {\pic} $P$, is that the maximum number of euler zones within it is @@ -300,12 +303,28 @@ a contour, we change the nature of the zones within the {\pic}, but the number of zones contributed by the {\pic} stays the same. \begin{definition} -A pure intersection chain has a maximum number of possible Euler zones, and exists as independent entities in the diagram. This -allows us to analyses {\pic}s separately, thus reducing the $2^N$ overhead of analysing an Euler diagram for available zones. +\label{picreduction} +The number of available zones within a {\pic} $P$ does not change +when other contours are added or removed from the diagram +that are not, or would not become members of the {\pic} $P$. \end{definition} -This is to say, the the number of zones within a {\pic} is not affected by changes in the diagram +his is to say, the the number of zones within a {\pic} is not affected by changes in the diagram that do not alter the {\pic}. +This allows us to analyses {\pic}s separately, thus reducing the $2^N$ overhead of analysing an Euler diagram for available zones. +\subsection{Available Zone Searching} + +The available zones in an Euler diagram represent set theoretic combinations +that can be used in the diagram. +%For FMMD analyis, the test~cases +Searching for an available zone involves finding out if the intersection exists, and then determining whether it is covered up +by any other contours. A brute force search for available zones using area operations +is therefore of the order $N.2^N$ (where N is the number of contours in the diagram). +By using the result in definition \ref{picreduction}, we can break the diagram into small segments +(the {\pic}s) which have an order $|P|.2^{|P|}$. +The order of area operations is generally\footnote{In the case where the diagram is not comprised of just one {\pic}, which has no enclosing contours} +reduced by requiring several $|P|.2^{|P|}$ +instead of $N.2^N$ as $P \leq N$. \vspace{40pt}