English

Existence of symmetric maximal noncrossing collections of $k$-element sets

Combinatorics 2019-05-28 v2 Representation Theory

Abstract

We investigate the existence of maximal collections of mutually noncrossing kk-element subsets of {1,,n}\left\{ 1, \dots, n \right\} that are invariant under adding k(modn)k\pmod n to all indices. Our main result is that such a collection exists if and only if kk is congruent to 0,10, 1 or 1-1 modulo n/GCD(k,n)n/\operatorname{GCD}(k,n). Moreover, we present some algebraic consequences of our result related to self-injective Jacobian algebras.

Keywords

Cite

@article{arxiv.1808.03556,
  title  = {Existence of symmetric maximal noncrossing collections of $k$-element sets},
  author = {Andrea Pasquali and Erik Thörnblad and Jakob Zimmermann},
  journal= {arXiv preprint arXiv:1808.03556},
  year   = {2019}
}

Comments

12 pages, 1 figure. Final version, to appear in Journal of Algebraic Combinatorics