Iterator1</code> where all
  except the first element of the elements comparing equal according
  to the ordering function <code>Fun</code> have been deleted. <code>Fun(A, B)</code> is to
  return <code>true</code> if <code>A</code> compares less than or equal to <code>B</code> in the ordering,
  otherwise <code>false</code>.</p>
 
  The iterator will be fully evaluated, infinite iterators will never
  return.</p>

<h3 class="function"><a name="zip-2">zip/2</a></h3>
<div class="spec">
<p><tt>zip(Iterator1, 