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	<entry>
		<id>https://en.formulasearchengine.com/w/index.php?title=Viennot%27s_geometric_construction&amp;diff=27527</id>
		<title>Viennot&#039;s geometric construction</title>
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		<updated>2013-08-10T22:07:42Z</updated>

		<summary type="html">&lt;p&gt;129.10.71.225: /* The construction */&lt;/p&gt;
&lt;hr /&gt;
&lt;div&gt;In mathematics and computer science, an &#039;&#039;&#039;event structure&#039;&#039;&#039; represents a set of events, some of which can only be performed after another (there is a &#039;&#039;dependency&#039;&#039; between the events) and some of which might not be performed together (there is a &#039;&#039;conflict&#039;&#039; between the events).&lt;br /&gt;
&lt;br /&gt;
== Formal definition ==&lt;br /&gt;
An &#039;&#039;&#039;event structure&#039;&#039;&#039; &amp;lt;math&amp;gt;(E,\leq,\#)&amp;lt;/math&amp;gt; consists of&lt;br /&gt;
* a set &amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt; of &#039;&#039;&#039;events&#039;&#039;&#039;&lt;br /&gt;
* a [[partial order]] relation on &amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt; called &#039;&#039;&#039;causal dependency&#039;&#039;&#039;,&lt;br /&gt;
* an [[irreflexive]] [[symmetric]] relation &amp;lt;math&amp;gt;\#&amp;lt;/math&amp;gt; called &#039;&#039;&#039;incompatibility&#039;&#039;&#039; (or &#039;&#039;&#039;conflict&#039;&#039;&#039;)&lt;br /&gt;
such that&lt;br /&gt;
* &#039;&#039;finite causes&#039;&#039;: for every event &amp;lt;math&amp;gt;e\in E&amp;lt;/math&amp;gt;, the set &amp;lt;math&amp;gt;[e]=\{f\in E|f\leq e\}&amp;lt;/math&amp;gt; of predecessors of &amp;lt;math&amp;gt;E&amp;lt;/math&amp;gt; is finite&lt;br /&gt;
* &#039;&#039;hereditary conflict&#039;&#039;: for every events &amp;lt;math&amp;gt;d,e,f\in E&amp;lt;/math&amp;gt;, if &amp;lt;math&amp;gt;d\leq e&amp;lt;/math&amp;gt; and &amp;lt;math&amp;gt;d\# f&amp;lt;/math&amp;gt; then &amp;lt;math&amp;gt;e\# f&amp;lt;/math&amp;gt;.&lt;br /&gt;
&lt;br /&gt;
== References ==&lt;br /&gt;
* {{cite article | last = Winskel | first = Glynn | url = http://www.cl.cam.ac.uk/~gw104/EvStr.pdf | title = Event Structures | journal = Advances in Petri Nets | publisher = Springer | series = Lecture Notes in Computer Science | year = 1987}}&lt;br /&gt;
&lt;br /&gt;
[[Category:Computing terminology]]&lt;br /&gt;
&lt;br /&gt;
&lt;br /&gt;
{{math-stub}}&lt;/div&gt;</summary>
		<author><name>129.10.71.225</name></author>
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