The trinacria graphs $T_{(b+2)b2}$ are $e$-positive
Combinatorics
2025-12-29 v1
Abstract
In this paper, we identify a new family of -positive graphs, called the trinacria graphs , thereby providing a partial answer to Stanley's question on which graphs are -positive. The trinacria graph is the graph on vertices obtained by attaching paths , and~ to the vertices of a triangle, respectively. Our proof relies on several ad hoc combinatorial ideas, and employs divide-and-conquer techniques, charging arguments, and progressive repair methods.
Cite
@article{arxiv.2512.21864,
title = {The trinacria graphs $T_{(b+2)b2}$ are $e$-positive},
author = {Simon Y. M. Gong and David G. L. Wang and K. Zhang},
journal= {arXiv preprint arXiv:2512.21864},
year = {2025}
}