mpare_subs_empty_post" class="anchored"><a href="#val-compare_subs_empty_post" class="anchor"></a><code><span><span class="keyword">val</span> compare_subs_empty_post : <a href="#type-comparator">comparator</a> * <a href="#type-comparator">comparator</a></span></code></div><div class="spec-doc"><p>Compare two subroutines by composition for an empty postcondition:</p><p>Given two subroutines and environments, return a postcondition and hypothesis that, when passed to <code>compare_subs</code>, will generate 