="md-nav__item">
  <a href="#st-x-survival-function" title="S(t, x), Survival function" class="md-nav__link">
    S(t, x), Survival function
  </a>

</li>

        <li class="md-nav__item">
  <a href="#ht-x-hazard-function-and-rx-risk-score" title="h(t, x), hazard function and r(x) risk score" class="md-nav__link">
    h(t, x), hazard function and r(x) risk score
  </a>

</li>





    </ul>

</nav>

  </li>







  <li class="md-nav__item md-nav__item--nested">

      <input class="md-toggle md-nav__toggl