Skew characteristic polynomial of graphs and embedded graphs
Abstract
We introduce a new one-variable polynomial invariant of graphs, which we call the skew characteristic polynomial. For an oriented simple graph, this is just the characteristic polynomial of its anti-symmetric adjacency matrix. For nonoriented simple graphs the definition is different, but for a certain class of graphs (namely, for intersection graphs of chord diagrams), it gives the same answer if we endow such a graph with an orientation induced by the chord diagram. We prove that this invariant satisfies Vassiliev's -term relations and determines therefore a finite type knot invariant. We investigate the behaviour of the polynomial with respect to the Hopf algebra structure on the space of graphs and show that it takes a constant value on any primitive element in this Hopf algebra. We also provide a two-variable extension of the skew characteristic polynomial to embedded graphs and delta-matroids. The -term relations for the extended polynomial prove that it determines a finite type invariant of multicomponent links.
Keywords
Cite
@article{arxiv.2201.07084,
title = {Skew characteristic polynomial of graphs and embedded graphs},
author = {R. Dogra and S. Lando},
journal= {arXiv preprint arXiv:2201.07084},
year = {2024}
}