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  "body": "\n## Summary\n\nIn the study of [[permutations|05RWFKVTJ7]] and permutation patterns, a **permutation class** is a set $C$ of permutations for which every pattern within a permutation in $C$ is also in $C$. In other words, a permutation class is a hereditary property of permutations, or a downset in the permutation pattern order. A permutation class may also be known as a **pattern class**, **closed class**, or simply **class** of permutations.\n",
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