w">&#45;&gt;</span></span> <span><a href="#type-t">t</a> list</span></span></code></div><div class="spec-doc"><p><code>power s</code> computes the power set of <code>s</code>. <b>Note</b>: the result is returned as a <em>list</em> of sets because sets of sets cannot be defined easily in a functorial way..</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-extract"><a href="#val-extract" class="anchor"></a><code><span><span class="keyword">val</span> extract : <span><a href="#type