n> <span class="type-var">'final</span></code></dt><dt class="spec value" id="val-exists"><a href="#val-exists" class="anchor"></a><code><span class="keyword">val</span> exists : <span><span class="type-var">'a</span> <a href="index.html#type-t">t</a></span> <span>&#45;&gt;</span> <span>f:<span>(<span class="type-var">'a</span> <span>&#45;&gt;</span> bool)</span></span> <span>&#45;&gt;</span> bool</code></dt><dt class="spec value" id="val-for_all"><a href="#val-for_all" class="anchor"></a><code><span class=