Results 41 to 50 of about 494 (99)

Algebraic atomistic lattices of quasivarieties

Algebra and Logic, 1997
Summary: The Gorbunov-Tumanov conjecture on the structure of lattices of quasivarieties is proven true for the case of algebraic lattices. Namely, for an algebraic atomistic lattice \(L\), the following conditions are equivalent: (1) \(L\) is represented as \(L_q(\mathcal K)\) for some algebraic quasivariety \(\mathcal K\); (2) \(L\) is represented as \
Adaricheva, K. V., Gorbunov, V. A., Dziobiak, W.   +2 more
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The lattice of quasivarieties of undirected graphs

Algebra Universalis, 2002
For a quasivariety \(\mathcal K\), let \(L(\mathcal K)\) denote the lattice of all quasivarieties contained in \(\mathcal K \). A quasivariety \(\mathcal K\) is said to be \(Q\)-universal if for any quasivariety \(\mathcal M\) of finite type, \(L(\mathcal M )\) is a homomorphic image of a sublattice of \(L(\mathcal K)\).
Adams, M. E., Dziobiak, W.
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Semigroup quasivarieties: Two lattices and a reopened problem

International Journal of Algebra and Computation, 2021
We determine all quasivarieties of aperiodic semigroups that are contained in some residually finite variety. This endeavor was initially motivated by a problem in natural dualities, but our work here also serves as a partial correction to an error found in a result of Sapir from the 1980s.
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Complexity of Quasivariety Lattices

Algebra and Logic, 2015
A quasivariety \(\mathbf K\) is a class of algebraic systems closed under isomorphisms, subsystems, direct products, and ultraproducts. The quasivarieties contained in a quasivariety \(\mathbf K\) form a complete lattice \(\mathbf{Lq(K)}\) under inclusion. Quasivariety lattices might be highly complex. A measure of complexity is given by the notion of \
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Congruence properties of lattices of quasivarieties

Algebra and Logic, 1997
Summary: The congruence properties close to lower boundedness in the sense of McKenzie are treated. In particular, an affirmative answer is obtained to a known question as to whether finite lattices of quasivarieties are lower bounded in the case where quasivarieties are congruence-Noetherian and locally finite.
Adaricheva, K. V., Gorbunov, V. A., Dziobiak, W.   +2 more
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UNREASONABLE LATTICES OF QUASIVARIETIES

International Journal of Algebra and Computation, 2012
A quasivariety is a universal Horn class of algebraic structures containing the trivial structure. The set [Formula: see text] of all subquasivarieties of a quasivariety [Formula: see text] forms a complete lattice under inclusion. A lattice isomorphic to [Formula: see text] for some quasivariety [Formula: see text] is called a lattice of ...
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Quasivariety Lattices of Pointed Abelian Groups

Algebra and Logic, 2014
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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Complexity of quasivariety lattices of pointed Abelian groups

Doklady Mathematics, 2012
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Imanaliev, M. I., Nurakunov, A. M.
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Finite distributive lattices of quasivarieties

Algebra and Logic, 1983
The paper contains an answer to the question: Is it possible to represent every finite distributive lattice by a lattice of quasivarieties? The answer is: For any distributive lattice L there exists a finitely generated, locally finite quasivariety M of finite type such that the lattice L is isomorphic to the lattice \(L_ q(M)\) of all subvarieties of ...
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Coverings in the lattice of quasivarieties of ℓ-groups

Siberian Mathematical Journal, 1992
See the review in Zbl 0772.06013.
Isaeva, O. V., Medvedev, N. Ya.
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