Vertex-transitive nut graph order-degree existence problem
Combinatorics
2026-01-14 v3 Number Theory
Abstract
A nut graph is a nontrivial simple graph whose adjacency matrix has a simple eigenvalue zero such that the corresponding eigenvector has no zero entries. It is known that the order and degree of a vertex-transitive nut graph satisfy , , and ; or , , and . Here, we prove that for each such and , there exists a -regular Cayley nut graph of order . As a direct consequence, we obtain all the pairs for which there is a -regular vertex-transitive (resp. Cayley) nut graph of order .
Keywords
Cite
@article{arxiv.2507.02481,
title = {Vertex-transitive nut graph order-degree existence problem},
author = {Ivan Damnjanović},
journal= {arXiv preprint arXiv:2507.02481},
year = {2026}
}