English

Arithmetical Structures on Coconut Trees

Combinatorics 2024-06-18 v1

Abstract

If G is a finite connected graph, then an arithmetical structure on GG is a pair of vectors (d,r)(\mathbf{d}, \mathbf{r}) with positive integer entries such that (\diag(d)A)r=0(\diag(\mathbf{d}) - A)\cdot \mathbf{r} = \mathbf{0}, where AA is the adjacency matrix of GG and the entries of r\mathbf{r} have no common factor other than 11. In this paper, we generalize the result of Archer, Bishop, Diaz-Lopez, Garc\'ia Puente, Glass, and Louwsma on enumerating arithmetical structures on bidents (also called coconut tree graphs \CTp2\CT{p}{2}) to all coconut tree graphs \CTps\CT{p}{s} which consists of a path on p>0p>0 vertices to which we append s>0s>0 leaves to the right most vertex on the path. We also give a characterization of smooth arithmetical structures on coconut trees when given number assignments to the leaf nodes.

Keywords

Cite

@article{arxiv.2406.11183,
  title  = {Arithmetical Structures on Coconut Trees},
  author = {Alexander Diaz-Lopez and Brian Ha and Pamela E. Harris and Jonathan Rogers and Theo Koss and Dorian Smith},
  journal= {arXiv preprint arXiv:2406.11183},
  year   = {2024}
}

Comments

18 pages, 9 figures, comments are welcomed

R2 v1 2026-06-28T17:08:06.895Z