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arXiv · 1810.02082

On toric ideals arising from signed graphs

JiSun Huh·Sangwook Kim·Boram Park
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Abstract

A signed graph is a pair $(G,\tau)$ of a graph $G$ and its sign $\tau$, where a \textit{sign} $\tau$ is a function from $\{ (e,v)\mid e\in E(G),v\in V(G), v\in e\}$ to $\{1,-1\}$. Note that graphs or digraphs are special cases of signed graphs. In this paper, we study the toric ideal $I_{(G,\tau)}$ associated with a signed graph $(G,\tau)$, and the results of the paper give a unified idea to explain some known results on the toric ideals of a graph or a digraph. We characterize all primitive binomials of $I_{(G,\tau)}$, and then focus on the complete intersection property. More precisely, we find a complete list of graphs $G$ such that $I_{(G,\tau)}$ is a complete intersection for every sign $\tau$.

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JiSun Huh, Sangwook Kim, Boram Park. 2018-10-04. On toric ideals arising from signed graphs. https://arxiv.org/abs/1810.02082

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