The pseudovariety $J$ is hyperdecidable
نویسندگان
چکیده
منابع مشابه
The Pseudovariety J is Hyperdecidable
— This article defines the notion of hyperdecidability for a class offinlte semigroups, which is closely connected to the notion of decidability. It then proves that the pseudovariety J of J-trivial semigroups is hyperdecidable.
متن کاملHyperdecidable Pseudovarieties and the Calculation of Semidirect Products
This note introduces the notion of a hyperdecidable pseudovariety. This notion appears naturally in trying to prove decidability of the membership problem of semidirect products of pseudovarieties of semigroups. It turns out to be a generalization of a notion introduced by C. J. Ash in connection with his proof of the \type II" theorem. The main results in this paper include a formulation of th...
متن کاملPseudovariety joins involving J -trivial semigroups and completely regular semigroups
J. Rhodes asked during the Chico conference in 1986 for the calculation of joins of semigroup pseudovarieties. This paper proves that the join J∨V of the pseudovariety J of J -trivial semigroups and of any 2-strongly decidable pseudovariety V of completely regular semigroups is decidable. This problem was proposed by the first author for V = G, the pseudovariety of finite groups.
متن کاملTameness of The Pseudovariety Ls1
A class of finite semigroups V is said to be decidable if the membership problem for V has a solution, that is, if we can construct an algorithm to test whether a given semigroup lies in V. Decidability of pseudovarieties is not preserved by some of the most common pseudovariety operators, such as semidirect product, Mal’cev product and join [1, 17]. In particular Rhodes [17] has exhibited a de...
متن کاملTameness of pseudovariety joins
The concept of tameness of a pseudovariety was introduced by Almeida and Steinberg [1] as a tool for proving decidability of the membership problem for semidirect products of pseudovarieties. Recall that the join V ∨ W of two pseudovarieties V and W is the least pseudovariety containing both V and W. This talk is concerned with the problem of proving tameness of joins. This problem was consider...
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ژورنال
عنوان ژورنال: RAIRO - Theoretical Informatics and Applications
سال: 1997
ISSN: 0988-3754,1290-385X
DOI: 10.1051/ita/1997310504571