an class="mord mtight" style=""><span class="mord mathnormal mtight coloredeq eql" style="">t</span></span></span></span><span style="top:-3.2198em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight" style=""><span class="mord mtight" style=""><span class="mopen mtight" style="">(</span><span class="mord mtight" style="">∞</span><span class="mclose mtight" style="">)</span></span></span></span></span><span class="vlist-s">​</span></span><