Saved in:
Bibliographic Details
Main Authors: Amsberry, K. J., Bergquist, J. A., Horstkamp, T. A., Lee, M. H., Yetter, D. N.
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2304.09747
Tags: Add Tag
No Tags, Be the first to tag this record!
Table of Contents:
  • Saki and Kiani proved that the subrack lattice of a rack $R$ is necessarily complemented if $R$ is finite but not necessarily complemented if $R$ is infinite. In this paper, we investigate further avenues related to the complementation of subquandles. Saki and Kiani's example of an infinite rack without complements is a quandle, which is neither ind-finite nor profinite. We provide an example of an ind-finite quandle whose subobject lattice is not complemented, and conjecture that profinite quandles have complemented subobject lattices. Additionally, we provide a complete classification of subquandles whose set-theoretic complement is also a subquandle, which we call \textit{strongly complemented}, and provide a partial transitivity criterion for the complementation in chains of strongly complemented subquandles. One technical lemma used in establishing this is of independent interest: the inner automorphism group of a subquandle is always a subquotient of the inner automorphism group of the ambient quandle.