Results 11 to 20 of about 775 (107)

Existentially prime Jonsson quasivarieties and their Jonsson spectra [PDF]

Қарағанды университетінің хабаршысы. Математика сериясы, 2022
This article is devoted to the study of Jonsson quasivarieties in a signature enriched with new predicate and constant symbols. New concepts of semantic Jonsson quasivariety and fragment-conservativeness of the center of the Jonsson theory are introduced.
A. Yeshkeyev, I. O. Tungushbayeva, S.M. Amanbekov   +2 more
semanticscholar   +4 more sources

Some non-standard quasivarieties of lattices [PDF]

Қарағанды университетінің хабаршысы. Математика сериясы, 2023
The questions of the standardness of quasivarieties have been investigated by many authors. The problem "Which finite lattices generate a standard topological prevariety?" was suggested by D.M. Clark, B.A. Davey, M.G. Jackson and J.G.
S. Lutsak, A. Basheyeva, A.M. Asanbekov, O. A. Voronina   +3 more
semanticscholar   +4 more sources

On Jonsson varieties and quasivarieties [PDF]

Қарағанды университетінің хабаршысы. Математика сериясы, 2021
In this paper, new objects of research are identified, both from the standpoint of model theory and from the standpoint of universal algebra. Particularly, the Jonsson spectra of the Jonsson varieties and the Jonsson quasivarieties are considered.
A. Yeshkeyev
semanticscholar   +4 more sources

Finite Lattices Generating Not Finitely–Based and Nonstandard Quasivarieties

Journal of Mathematics, Volume 2025, Issue 1, 2025.
There are two well‐known and closely related problems in lattice theory: Which finite lattices generate finitely‐based quasivarieties? and Which finite lattices generate standard quasivarieties? The main goal of the paper is to contribute to both problems.
M. A. Arapbay, A. O. Basheyeva, S. M. Lutsak, Ljubisa Kocinac   +3 more
wiley   +2 more sources

Note on quasivarieties generated by finite pointed abelian groups

Open Mathematics
We prove that a finite pointed abelian group generates a finitely axiomatizable variety that has a finite quasivariety lattice. As a consequence, we obtain that a quasivariety generated by a finite pointed abelian group has a finite basis of quasi ...
A. Basheyeva, S. Lutsak
semanticscholar   +2 more sources

Decidable quasivarieties of p‐algebras

Mathematical Logic Quarterly
Abstract We show that for quasivarieties of p‐algebras the properties of (i) having decidable first‐order theory and (ii) having decidable first‐order theory of the finite members, coincide. The only two quasivarieties with these properties are the trivial variety and the variety of Boolean algebras.
Tomasz Kowalski, Katarzyna Słomczyńska
openaire   +4 more sources

The Operator Ln on Quasivarieties of Universal Algebras

Siberian Mathematical Journal, 2019
Let $n$ be an arbitrary natural number and let $M$ be a class of universal algebras. Denote by $L_n(M)$ the class of algebras $G$ such that, for every $n$-generated subalgebra $A$ of $G$, the coset $a/R$ $(a\in A)$ modulo the least congruence $R$ including $A\times A$ is an algebra in $M$.
A. Budkin
openaire   +3 more sources

On quasi-identities of finite modular lattices. II [PDF]

Қарағанды университетінің хабаршысы. Математика сериясы, 2023
The existence of a finite identity basis for any finite lattice was established by R. McKenzie in 1970, but the analogous statement for quasi-identities is incorrect. So, there is a finite lattice that does not have a finite quasi-identity basis
A.O. Basheyeva, S.M. Lutsak
doaj   +3 more sources

On categoricity questions for universal unars and undirected graphs under semantic Jonsson quasivariety [PDF]

Қарағанды университетінің хабаршысы. Математика сериясы, 2023
The article is devoted to the study of semantic Jonsson quasivarieties of universal unars and undirected graphs. The first section of the article consists of basic necessary concepts from Jonsson model theory.
A.R. Yeshkeyev, A.R. Yarullina, S.M. Amanbekov   +2 more
doaj   +2 more sources

Admissibility in Finitely Generated Quasivarieties [PDF]

Logical Methods in Computer Science, 2013
Checking the admissibility of quasiequations in a finitely generated (i.e., generated by a finite set of finite algebras) quasivariety Q amounts to checking validity in a suitable finite free algebra of the quasivariety, and is therefore decidable ...
George Metcalfe, Christoph Röthlisberger   +1 more
doaj   +1 more source