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On varieties of ordered semigroups
We use syntactical methods (fully invariant stable quasiorders) to study varieties of ordered semigroups. We prove that the lattice of all varieties of semigroups is embedded into the lattice of all varieties of ordered
BA - Obecná matematika
- 2015 •
- Jx •
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Jx - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)
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Algebraic characterization of the finite power property
We give a transparent characterization, by means of a certain syntactic semigroup, of regular languages possessing the finite power property. Then we use this characterization to obtain a short elementary proof for the uniform decid...
BA - Obecná matematika
- 2006 •
- D
Rok uplatnění
D - Stať ve sborníku
Regular solutions of language inequalities and well quasi-orders
By means of constructing suitable well quasi-orders of free monoids we prove that all maximal solutions of certain systems of language inequalities are regular. This way we deal with a wide class of systems of inequalities where all constants are lan...
BA - Obecná matematika
- 2005 •
- Jx
Rok uplatnění
Jx - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)
Regular solutions of language inequalities and well quasi-orders
By means of constructing suitable well quasi-orders of free monoids we prove that all maximal solutions of certain systems of language inequalities are regular. This way we deal with a wide class of systems of inequalities where all constants are lan...
BA - Obecná matematika
- 2004 •
- D
Rok uplatnění
D - Stať ve sborníku
Towards a pseudoequational proof theory
A new scheme for proving pseudoidentities from a given set Sigma of pseudoidentities, which is clearly sound, is also shown to be complete in many instances, such as when Sigma defines a locally finite variety, a pseudovariety of groups, more general...
Pure mathematics
- 2018 •
- Jimp •
- Link
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Jimp - Článek v periodiku v databázi Web of Science
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On Kovács–Newman ordered semigroups
The irreducibility of pseudovarieties of semigroups is studied using many different approaches including a notion of Kovacs-Newman semigroups. In this note, we answer a natural question, whether Kovacs-Newman semigroups can...
Pure mathematics
- 2021 •
- Jimp •
- Link
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Jimp - Článek v periodiku v databázi Web of Science
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Identity Problems, Solvability of Equations and Unification in Varieties of Semigroups Related to Varieties of Groups
varieties of semigroups. We are interested in identity problems, in the solvability themin significant varieties of semigroups, monoids, groups, completely simple semigroups, completely regular semigroups (in part...
BA - Obecná matematika
- 2011 •
- D •
- Link
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D - Stať ve sborníku
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Rees semigroups of digraphs for classification of data
in semiring constructions based on semigroups. The present paper introduces Rees semigroups of directed graphs. This new construction is a common generalization of Rees matrix semigroups and incidence semigroups o...
BA - Obecná matematika
- 2016 •
- Jx •
- Link
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Jx - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)
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Uncountably many existence varieties of orthodox locally idempotent semigroups
It is shown that the cardinality of the sublattice of all existence varieties of orthodox semigroups occurring in the interval between the variety of all idempotent semigroups and the existence variety of all orthodox locally idempo...
BA - Obecná matematika
- 2004 •
- Jx
Rok uplatnění
Jx - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)
On bases of identities of finite central locally orthodox completely regular semigroups
semigroup has a finite basis of identities, and that every finite central completely simple semigroup has a finite basis of identities. In the present paper, a common locally orthodox completely regular semigroup has a fin...
Pure mathematics
- 2021 •
- Jimp •
- Link
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Jimp - Článek v periodiku v databázi Web of Science
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