Language Equations with Symmetric Difference

• Autorzy: Okhotin A.
• Języki publikacji: EN

Abstrakty

EN

The paper investigates the expressive power of language equations with the operations of concatenation and symmetric difference. For equations over every finite alphabet Σ with |Σ| ≥1, it is demonstrated that the sets representable by unique solutions of such equations are exactly the recursive sets over , and the sets representable by their least (greatest) solutions are exactly the recursively enumerable sets (their complements, respectively). If |Σ| ≥ 2, the same characterization holds already for equations using symmetric difference and linear concatenation with regular constants. In both cases, the solution existence problem is Π (0,1)-complete, the existence of a unique, a least or a greatest solution is Π(0,2)-complete, while the existence of finitely many solutions is Σ(0,3)-complete.

Słowa kluczowe

EN

language equations; symmetric difference

• Wydawca: IOS Press
• Czasopismo: Fundamenta Informaticae
• Rocznik: 2012
• Tom: Vol. 116, nr 1-4
• Strony: 205--222
• Opis fizyczny: Bibliogr. 31 poz.

Twórcy

autor

Okhotin A.

• Department of Mathematics, University of Turku Turku FI-20014, Finland,

Bibliografia

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