Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Enumerations of specific permutation classes
open-in-new
<p>In the study of <a href="/facts/Permutation_pattern/ytUU2b91">permutation patterns</a>, there has been considerable interest in enumerating specific <a href="/facts/Permutation_class/D9x7xIrT">permutation classes</a>, especially those with relatively few basis elements. This area of study has turned up unexpected instances of <a href="/facts/Wilf_equivalence/51YUu62f">Wilf equivalence</a>, where two seemingly-unrelated permutation classes have the same number of permutations of each length. </p>