Literally idempotent languages and their varieties - two letter case
Autoři | |
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Rok publikování | 2010 |
Druh | Článek v odborném periodiku |
Časopis / Zdroj | International Journal of Foundations of Computer Science |
Fakulta / Pracoviště MU | |
Citace | |
Obor | Obecná matematika |
Klíčová slova | varieties of regular languages; idempotent semigroups; syntactic monoids |
Popis | We already studied classes of literally idempotent languages closely related to the (positive) varieties of the famous Straubing- Thérien hierarchy. In the present paper we start a systematic study of literal varieties of literally idempotent languages, namely we deal with the case of two letter alphabet. First, we consider natural canonical expressions for such languages. Secondly, we describe all possible classes of the form V ({a, b}) where V is a literal variety of literally idempotent languages. |
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