pan>lhs:<a href="index.html#type-t">t</a></span> <span>&#45;&gt;</span> <span>rhs:<a href="index.html#type-t">t</a></span> <span>&#45;&gt;</span> bool</code></dt><dd><p>the implication relation: <code>lhs &lt;= rhs</code> means <code>lhs |- rhs</code></p></dd></dl></details></div></div></div><dl><dt class="spec value" id="val-join"><a href="#val-join" class="anchor"></a><code><span class="keyword">val</span> join : <a href="index.html#type-t">t</a> <span>&#45;&gt;</span> <a href="index.html#type-t">t</a> <s