 an exact operator can not be defined (None), the solver doesn't use the pruning features. precondition: the two abstract elements must be defined onto the same set of variables.</p></dd></dl><dl><dt class="spec value" id="val-split"><a href="#val-split" class="anchor"></a><code><span class="keyword">val</span> split : <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> <span><a href="index.html#type-t">t</a> list</span></code></dt><dd><p>splits an abstract element</p></dd></dl><section><header><h3 id=