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arXiv · 2304.12807

Submaximal clones over a three-element set up to minor-equivalence

Albert Vucaj·Dmitriy Zhuk
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Abstract

We study clones modulo minor homomorphisms, which are mappings from one clone to another preserving arities of operations and respecting permutation and identification of variables. Minor-equivalent clones satisfy the same sets of identities of the form $f(x_1,\dots,x_n)\approx g(y_1,\dots,y_m)$, also known as minor identities, and therefore share many algebraic properties. Moreover, it was proved that the complexity of the $\operatorname{CSP}$ of a finite structure $\mathbb{A}$ only depends on the set of minor identities satisfied by the polymorphism clone of $\mathbb{A}$. In this article we consider the poset that arises by considering all clones over a three-element set with the following order: we write $\mathcal{C} \preceq_{\mathrm{m}} \mathcal{D}$ if there exists a minor homomorphism from $\mathcal{C}$ to $\mathcal{D}$. We show that the aforementioned poset has only three submaximal elements.

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Albert Vucaj, Dmitriy Zhuk. 2023-04-25. Submaximal clones over a three-element set up to minor-equivalence. https://arxiv.org/abs/2304.12807

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