> is a slot name such that <code>(slot-exists-p <var>F</var> <var>R</var>)</code> gives <code class="other-name">nil</code> then:
<ul>
  <li><code>(slot-boundp <var>F</var> <var>R</var>)</code> gives <code class="other-name">nil</code> as well (instead of raising an error);</li>
  <li><code>(slot-value <var>F</var> <var>R</var>)</code> signals an error of type <code class="other-name">unbound-slot</code>;</li>
  <li><code>(slot-makunbound <var>F</var> <var>R</var>)</code> does nothing and returns <var>F</va