<?xml version="1.0" encoding='utf-8'?>
<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml">
<wml>
<card id="card1" title="Trapezoid graph - Page 2 - Wikipedia">
<p>
<a accesskey="1" href="page.php?w=trapezoid_graph&amp;p=1">1.Previous</a><br />
<a accesskey="3" href="page.php?w=trapezoid_graph&amp;p=3">3.Next</a>
</p>
<p>vertices are joined by an edge if and only if the corresponding trapezoids intersect. Trapezoid graphs were introduced by <a href="page.php?w=Ido_Dagan">Dagan</a>, <a href="page.php?w=Martin_Charles_Golumbic">Golumbic</a>, and <a href="page.php?w=Ron_Pinter">Pinter</a> in 1988. There exists  algorithms for chromatic number, weighted <a href="page.php?w=Independent_set_%28graph_theory%29">independent set</a>, clique cover, and maximum weighted clique.</p>

<p><big> Definitions and characterizations </big></p>
<p>Given a channel, a pair of two horizontal</p><p>
<a accesskey="1" href="page.php?w=trapezoid_graph&amp;p=1">1.Previous</a><br />
<a accesskey="3" href="page.php?w=trapezoid_graph&amp;p=3">3.Next</a>
</p>

<do type="prev" label="Search">
        <go href="search.wml"/>
</do>

</card>
</wml>
