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Well quasi-orders and the shuffle closure of finite sets

Flavio D'Alessandro·Gwénaël Richomme·Stefano Varrichio
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Abstract

Given a set I of word, the set of all words obtained by the shuffle of (copies of) words of I is naturally provided with a partial order. In [FS05], the authors have opened the problem of the characterization of the finite sets I such that the order is a well quasi-order . In this paper we give an answer in the case when I consists of a single word w.

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Flavio D'Alessandro, Gwénaël Richomme, Stefano Varrichio. 2006-07-18. Well quasi-orders and the shuffle closure of finite sets. https://arxiv.org/abs/cs/0607082

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