nbsp;<span class="keywordsign">'</span>a&nbsp;t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;<span class="keywordsign">'</span>b&nbsp;t&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;k&nbsp;option<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;domains_disjoint&nbsp;:&nbsp;<span class="keywordsign">'</span>a&nbsp;t&nbsp;list&nbsp;<span class="keywordsign">-&gt;</span>&nbsp;bool<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<span class="keyword">val</span>&nbsp;iter&nbsp;:&nbsp;