Circular sorting in the alternating group
Abstract
The symmetric group is generated by transpositions, and problems of sorting permutations using transpositions are well studied. In recent work, Adin, Alon, and Roichman studied the related problem of sorting points on a circle, and gave a formula for the maximum number of adjacent swaps required. This is equivalent to the number of adjacent transpositions required to transform any permutation into a power of the cyclic permutation . The focus of this work is an analogous question in the alternating group , which is generated by -cycles. That is, using 3-cycles instead of transpositions, what is the maximum number of steps required to transform an even permutation into a power of in the alternating group? We determine this number exactly for even and . For , we show that the sorting number can take one of two possible values and give explicit constructions demonstrating that the larger value occurs infinitely often.
Cite
@article{arxiv.2608.06338,
title = {Circular sorting in the alternating group},
author = {Melanie Ferreri and Eric Swartz and Nicholas J. Werner},
journal= {arXiv preprint arXiv:2608.06338},
year = {2026}
}
Comments
20 pages