English

Symmetric Chromatic Polynomial of Trees

Combinatorics 2015-05-13 v2

Abstract

In a 1995 paper Richard Stanley defined XGX_G, the symmetric chromatic polynomial of a Graph G=(V,E)G=(V,E). He then conjectured that XGX_G distinguishes trees; a conjecture which still remains open. XGX_G can be represented as a certain collection of integer partitions of V|V| induced by each SES\subseteq E, which is very approachable with the aid of a computer. Our research involved writing a computer program for efficient verification of this conjecture for trees up to 23 vertices. In this process, we also gather trees with matching collections of integer partitions of a fixed number of parts. For each k=2,3,4,5k=2, 3, 4, 5, we provide the smallest pair of trees whose partitions of kk parts agree. In 2013, Orellana and Scott give a proof of a weaker version of Stanely's conjecture for trees with one centroid. We prove a similar result for arbitrary trees, and provide examples to show that this result, combined with that of Orellana and Scott, is optimal.

Keywords

Cite

@article{arxiv.1505.01889,
  title  = {Symmetric Chromatic Polynomial of Trees},
  author = {Isaac Smith and Zane Smith and Peter Tian},
  journal= {arXiv preprint arXiv:1505.01889},
  year   = {2015}
}