<?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="Binary relation - Page 6 - Wikipedia">
<p>
<a accesskey="1" href="page.php?w=Binary_relation&amp;p=5">1.Previous</a><br />
<a accesskey="3" href="page.php?w=Binary_relation&amp;p=7">3.Next</a>
</p>
<p>(<a href="page.php?w=Union_%28set_theory%29">union</a>, <a href="page.php?w=Intersection_%28set_theory%29">intersection</a>, and <a href="page.php?w=Complement_%28set_theory%29">complementation</a>) and <a href="page.php?w=algebra_of_sets">algebra of sets</a>. </p>

<p>In some systems of <a href="page.php?w=axiomatic_set_theory">axiomatic set theory</a>, relations are extended to <a href="page.php?w=Class_%28mathematics%29">classes</a>, which are generalizations of sets. This extension is needed for, among other things, modeling the concepts</p><p>
<a accesskey="1" href="page.php?w=Binary_relation&amp;p=5">1.Previous</a><br />
<a accesskey="3" href="page.php?w=Binary_relation&amp;p=7">3.Next</a>
</p>

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

</card>
</wml>
