alues are
&ldquo;default true&rdquo; and &ldquo;default false&rdquo;. However, the present
discussion defers the subject of default truth values.
</p><h3><a name="FOOT5" href="manual_3.html#DOCF5">(5)</a></h3>
<p>Because proving negations can be very difficult,
PowerLoom will only conduct a very quick and shallow search for a
disproof.  More extensive reasoning is used if a negation is asked
about explicitly, thus PowerLoom may return <code>unknown</code> if asked
about <code>P</code>, but true if asked abo