Reverted last change, since it caused incompatibilities.
<ul>
<li>Higher-Order Logic</li>
<li style="list-style: none">
<ul>
<li><a href="HOL/index.html">HOL (Higher-Order Logic)</a></li>
<li><a href="HOLCF/index.html">HOLCF (Higher-Order Logic of Computable Functions)</a></li>
</ul>
</li>
</ul>
<ul>
<li>First-Order Logic</li>
<li style="list-style: none">
<ul>
<li><a href="FOL/index.html">FOL (Many-sorted First-Order Logic)</a></li>
<li><a href="ZF/index.html">ZF (Set Theory)</a></li>
<li><a href="CCL/index.html">CCL (Classical Computational Logic)</a></li>
<li><a href="LCF/index.html">LCF (Logic of Computable Functions)</a></li>
<li><a href="FOLP/index.html">FOLP (FOL with Proof Terms)</a></li>
</ul>
</li>
</ul>
<ul>
<li>Miscellaneous</li>
<li style="list-style: none">
<ul>
<li><a href="Sequents/index.html">Sequents (first-order, modal and linear logics)</a></li>
<li><a href="CTT/index.html">CTT (Constructive Type Theory)</a></li>
<li><a href="Cube/index.html">Cube (The Lambda Cube)</a></li>
</ul>
</li>
</ul>