tes/index.html#type-t">States.t</a></span></code></div><div class="spec-doc"><p><code>preds s q</code> returns the set of immediate predecessors of state <code>q</code> in <code>s</code>, <i>i.e.</i> the set of state <code>q'</code> such that there exists a transition <code>(q',l,q)</code> in <code>R</code>. Raise Invalid_argument if <code>q</code> is not in <code>s</code>.</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-preds'"><a href="#val-preds'" class="anchor"></a><code><