ndefined if <code>f</code> is not injective its first argument.</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-map_label"><a href="#val-map_label" class="anchor"></a><code><span><span class="keyword">val</span> map_label : <span><span>(<span><a href="Transition/index.html#type-t">Transition.t</a> <span class="arrow">&#45;&gt;</span></span> <a href="Transition/index.html#type-t">Transition.t</a>)</span> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-t">t</a> 