Results 31 to 40 of about 95 (81)

Joins of minimal quasivarieties

Studia Logica, 1995
Let \({\mathcal D}_2\) denote the variety of algebras \((L;\wedge, \vee, 0, c_0, c_1,1)\) which are distributive \((0,1)\)-lattices with two distinguished elements \(c_0, c_1\in L\). It is known that the only subdirectly irreducible algebras in \({\mathcal D}_2\) are \(2_{ij}= (\{0, 1\};\wedge, \vee, 0, i,j, 1)\) with \(i,j\in \{0, 1\}\). Let, further,
M E Adams, Dziobiak W, W Dziobiak
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SUBFUNCTORS ASSOCIATED WITH QUASIVARIETIES

1984
Quasivarieties of algebras are characterized as SP-classes closed under a certain construction of directed unions of congruences.
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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 \(L(\mathcal K)\).
M E Adams, Dziobiak W, W Dziobiak
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Least V-quasivarieties of MV-algebras

Fuzzy Sets and Systems, 2016
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Joan Gispert
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Categorial quasivarieties

Algebra and Logic, 1972
E A Palyutin, Palyutin E A
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Profinite Locally Finite Quasivarieties

Studia Logica, 2023
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
Anvar M. Nurakunov, Marina Schwidefsky
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QUASIVARIETIES OF IDEMPOTENT SEMIGROUPS

International Journal of Algebra and Computation, 2003
It is proved that the lattice L(Bd) of quasivarieties contained in the variety Bdof idempotent semigroups contains an isomorphic copy of the ideal lattice of a free lattice on ω free generators. This result shows that a problem of Petrich [19], which calls for a description of L(Bd), is much more complex than originally expected.
M. E. Adams, Wieslaw Dziobiak
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ASSERTIONALLY EQUIVALENT QUASIVARIETIES

International Journal of Algebra and Computation, 2008
A translation in an algebraic signature is a finite conjunction of equations in one variable. On a quasivariety K, a translation τ naturally induces a deductive system, called the τ-assertional logic of K. Two quasivarieties are τ-assertionally equivalent if they have the same τ-assertional logic. This paper is a study of assertional equivalence.
Willem J. Blok, James G. Raftery 0001
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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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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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