Results 21 to 30 of about 95 (81)

How to Sketch Quasivarieties

Journal of Algebra, 1996
The author describes a class of sketches, ``separated limit sketches'', such that quasivarieties of finitary algebras are precisely the categories sketchable by separated finite-limit sketches. This result has an extension with ``finitary'' replaced by a cardinal parameter.
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Properties of semigroups of elementary types of model classes

Қарағанды университетінің хабаршысы. Математика сериясы
The study of classes of first-order countable language models and their properties is an important direction in model theory. Of particular interest are axiomatizable classes of models (varieties, quasivarieties, finitely axiomatizable classes ...
A. Kabidenov, A. Kassatova, M. Bekenov, A. Mamyraly   +3 more
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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 ...
Basheyeva Ainur, Lutsak Svetlana
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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
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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 $M$.
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Sequent calculi and quasivarieties

Reports Math. Log., 2000
Summary: We discuss relatively point-regular quasivarieties related in some special sense to sequent calculi. We show that the free algebra in such a quasivariety is Fregean iff in the sequent calculus the so-called symmetric contraction rules are admissible. In the presence of the fusion connective this is equivalent to having contraction.
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Convex congruences. [PDF]

Soft comput, 2017
Chajda I, Länger H.
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Counting quasivarieties of equivalential algebras [PDF]

Reports Math. Log., 2000
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Rectangular groupoids and related structures.

Discrete Math, 2013
Boykett T.
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Quasivarieties of distributivep-algebras

Algebra Universalis, 1992
The paper exhibits three results on quasivarieties of (distributive) \(p\)- algebras: There exists a quasivariety \(\mathbb{K}\) of such algebras such that \(\mathbb{B}_ 2\subset\mathbb{K}\subset\mathbb{B}_ 4\), but neither \(\mathbb{K}\subseteq\mathbb{B}_ 3\) nor \(\mathbb{B}_ 3\subseteq\mathbb{K}\), where \(\mathbb{B}_ i\) denotes the \(i\)-th Lee ...
Hernando G Gaitan
exaly   +3 more sources