Boolean value indicating whether the initial elements of the
sequence are equivalent to the elements in another sequence, using
the given predicate as the equivalence test.</p>
<p>The predicate must be a <em>equivalence relation</em> over the elements. That
is, for any elements <code>a</code>, <code>b</code>, and <code>c</code>, the following conditions must
hold:</p>
<blockquote>
<p>Complexity:
O(<em>m</em>), where <em>m</em> is the lesser of the length of the sequence and the length of <code>possiblePrefi