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arXiv · 1604.05223

On sets of irreducible polynomials closed by composition

Andrea Ferraguti·Giacomo Micheli·Reto Schnyder
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Abstract

Let $\mathcal S$ be a set of monic degree $2$ polynomials over a finite field and let $C$ be the compositional semigroup generated by $\mathcal S$. In this paper we establish a necessary and sufficient condition for $C$ to be consisting entirely of irreducible polynomials. The condition we deduce depends on the finite data encoded in a certain graph uniquely determined by the generating set $\mathcal S$. Using this machinery we are able both to show examples of semigroups of irreducible polynomials generated by two degree $2$ polynomials and to give some non-existence results for some of these sets in infinitely many prime fields satisfying certain arithmetic conditions.

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Andrea Ferraguti, Giacomo Micheli, Reto Schnyder. 2016-04-18. On sets of irreducible polynomials closed by composition. https://doi.org/10.1007/978-3-319-55227-9_6

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