<?xml version="1.0"?>

<rulebase>

<!-- non-ground-fact-like rule with 4-ary cterm as single argument -->

<fact>
  <_head>
    <atom>
      <_opr><rel>book</rel></_opr>
      <cterm>
        <_opc><ctor>parts</ctor></_opc>
        <var>title</var>
        <var>autor</var>
        <var>toc</var>
        <var>chapters</var>
      </cterm>
    </atom>
  </_head>
</fact>

</rulebase>
