论文信息 - A Note on Decidability Questions on Presentations of Word Semigroups

A Note on Decidability Questions on Presentations of Word Semigroups

We apply automata-theoretic tools and some recently established compactness properties in the study of F-semigroups, that is, subsemigroups of free semigroups. With each F-semigroup we associate an F-presentation, which turns out to be finite for all finitely generated F-semigroups. Connections between F-presentations and ordinary presentations of semigroups are also pointed out. It is also shown that it is undecidable whether two finitely generated F-semigroups satisfy a common relation in their F-presentation.

Tero Harju | Christian Choffrut | Juhani Karhumäki

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