The graph of a sequence of numbers, showing pairs of consecutive sequence values (thick red edges) that bracket a given value <i>x</i>. In a sorting algorithm by Levcopoulos &amp; Petersson (1989) based on <a href="https://en.wikipedia.org/wiki/Cartesian_tree" class="extiw" title="en:Cartesian tree">Cartesian trees</a>, the time to include <i>x</i> in the sorted order is proportional to the logarithm of this number of bracketing pairs.
<a href="//commons.wikimedia.org/wiki/User:David_Eppstein" class="mw-redirect" title="User:David Eppstein">David Eppstein</a>
<span class="int-own-work" lang="en">Own work</span>