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arXiv · 2504.09051

The varieties generated by 3-hypergraph semirings

Yuanfan Zhuo·Xingliang Liang·Yanan Wu·Xianzhong Zhao
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Abstract

In this paper the 3-hypergraph semigroups and 3-hypergraph semirings from 3-hypergraphs $\mathbb{H}$ are introduced and the varieties generated by them are studied. It is shown that all 3-hypergraph semirings $S_{\scriptscriptstyle \mathbb{H}}$ are nonfinitely based and subdirectly irreducible. Also, it is proved that each variety generated by 3-hypergraph semirings is equal to a variety generated by 3-uniform hypergraph semirings. It is well known that both variety $\mathbf{V}(S_c(abc))$ (see, J. Algebra 611: 211--245, 2022 and J. Algebra 623: 64--85, 2023) and variety $\mathbf{V}(S_{\scriptscriptstyle \mathbb{H}})$ play key role in the theory of variety of ai-semirings, where 3-uniform hypergraph $\mathbb{H}$ is a 3-cycle. They are shown that each variety generated by 2-robustly strong 3-colorable 3-uniform hypergraph semirings is equal to variety $\mathbf{V}(S_c(abc))$, and each variety generated by so-called beam-type hypergraph semirings or fan-type hypergraph semirings is equal to the variety $\mathbf{V}(S_{\scriptscriptstyle \mathbb{H}})$ generated by a 3-uniform 3-cycle hypergraph semiring $S_{\scriptscriptstyle \mathbb{H}}$. Finally, an infinite ascending chain is provided in the lattice of subvarieties of the variety generated by all 3-uniform hypergraph semirings. This implies that the variety generated by all 3-uniform hypergraph semirings has infinitely many subvarieties.

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Yuanfan Zhuo, Xingliang Liang, Yanan Wu, Xianzhong Zhao. 2025-04-12. The varieties generated by 3-hypergraph semirings. https://arxiv.org/abs/2504.09051

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