i>
</ul>
<ul>
<li>it it monotonous: the sum of components always increase, eg.
      <code class="code">|succ x| &gt;= |x|</code>, where <code class="code">|None|</code> is <code class="code">max_int</code>, <code class="code">|Some x| = |x|</code>
      and <code class="code">|(x_1,...,x_n) = x_1 + ... + x_n|</code>.</li>
</ul>

    That enumeration encodes the heuristic we are trying to implement,
    which is: we first try to install the 'ideal' state, where all
    packages are installed with their most