Pattern avoidance enumerated by inversions

Atli Fannar Franklín

Published 2024-10-09Version 1

Permutations are usually enumerated by size, but new results can be found by enumerating them by inversions instead, in which case one must restrict one's attention to indecomposable permutations. In the style of the seminal paper by Simion and Schmidt, we investigate all combinations of permutation patterns of length at most 3.