>convert between system and description</p></li>
</ul>
</li>
<li><p>kaffman‚Äôs number of conflicting constraints</p></li>
<li><p>Effective complexity (Gell-Mann, 1995) measures the minimal description length of a system‚Äôs regularities</p></li>
<li><p>Physical complexity (Adami and Cerf, 2000) is related to effective complexity and is designed to estimate the complexity of any sequence of symbols that is about a physical world or environment</p></li>
<li><p>Statistical complexity (Crutchfield and 