<?xml version="1.0"?>

<rulebase
xmlns="http://www.ruleml.org/0.86/xsd"
xsi:schemaLocation="http://www.ruleml.org/0.86/xsd http://www.ruleml.org/0.86/xsd/urdatalog.xsd"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>

<!-- challenge rule from RuleML site -->

<imp>
  <_head>
    <atom>
      <_opr>
        <rel>may look at</rel>
      </_opr>
      <var>you</var>
      <ind href="http://www.cs.brandeis.edu/...">Rule-Based Systems</ind>
    </atom>
  </_head>
  <_body>
    <atom>
      <_opr>
        <rel>want to review</rel>
      </_opr>
      <var>you</var>
      <ind>rule principles</ind>
    </atom>
  </_body>
</imp>

<fact>
 <_head>
  <atom>
    <_opr>
      <rel>want to review</rel>
    </_opr>
    <ind>fred</ind>
    <ind>rule principles</ind>
  </atom>
 </_head>
</fact>


</rulebase>

