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<p>In this case, the elements of the set are usually referred to as executions of the system.</p>

<p>The name prefix order stems from the prefix order on words, which is a special kind of <a href="page.php?w=substring">substring</a> relation and, because of its discrete character, a tree.</p>

<p><big> Formal definition </big></p>
<p>A <b>prefix order</b> is a <a href="page.php?w=binary_relation">binary relation</a> "<=" over  a <a href="page.php?w=Set_%28mathematics%29">set P which is <a href="page.php?w=antisymmetric_relation">antisymmetric</a>, <a href="page.php?w=transitive_relation">transitive</a>, <a href="page.php?w=reflexive_relation">reflexive</a>, and <b>downward total</b>, i.e., for all a, b, and c in P, we have that:</="></p><p>
<a accesskey="1" href="page.php?w=prefix_order&amp;p=1">1.Previous</a><br />
<a accesskey="3" href="page.php?w=prefix_order&amp;p=3">3.Next</a>
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