Results 51 to 60 of about 494 (99)

Quasivarieties of lattice-ordered groups

1994
An implication of the signature l = {·, -1, e, ∨, ∧} is a formula φ of the predicate calculus of the form $$\left( {\forall {x_1}} \right) \ldots \left( {\forall {x_n}} \right)\left( {{w_1}\left( {{x_1}, \ldots ,{x_n}} \right) = e\& \ldots \& {w_k}\left( {{x_1}, \ldots {x_n}} \right) = e \Rightarrow \Rightarrow {w_{k + 1}}\left( {{x_{1,}} \ldots ...
V. M. Kopytov, N. Ya. Medvedev
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Quasivarieties of orthomodular lattices and Bell inequalities

Reports on Mathematical Physics, 1996
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D'Andrea, Anna Bruna, Pulmannová, Sylvia   +1 more
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Lattices of quasivarieties of unars

Siberian Mathematical Journal, 1986
Translation from Sib. Mat. Zh. 26, No.3(151), 49-62 (Russian) (1985; Zbl 0569.08005).
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The lattice of quasivarieties of commutative moufang loops

Algebra and Logic, 1998
Previously, the author proved [Algebra Logika 30, No. 6, 726-734 (1991; Zbl 0778.20027)] that a quasivariety generated by a finitely generated commutative Moufang loop \(L\) has a finite basis of quasi-identities if and only if \(L\) is a group. In the article under review, it is proven that the lattice of quasivarieties of an arbitrary variety ...
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The lattice of quasivarieties of semigroups

Algebra Universalis, 1985
A quasivariety is a class of similar algebras which is closed under the formation of subalgebras, products and ultra-products (equivalently, definable by ''quasi-identities'' or ''implications''). The quasivariety generated by an algebra A is denoted Q(A). The lattice of subquasivarieties of a quasivariety \({\mathcal K}\) is denoted L(\({\mathcal K}).\
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A quasivariety lattice of torsion-free soluble groups

Algebra and Logic, 2011
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A lattice of quasivarieties of nilpotent groups

Algebra and Logic, 1994
Let \(qG\) denote the quasivariety generated by a group \(G\). \textit{A. Fedorov} [VINITI, No. 5489-B87, Moscow (1987)] classified all finite nilpotent groups of class 2 generating quasivarieties which contain only finitely many subquasivarieties, and showed that for any other finite nilpotent group \(H\) of class 2, \(qH\) contains uncountably many ...
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The structure of the lattices of quasivarieties

Algebra Universalis, 1994
For an algebraic system \(A\) and a quasivariety \(\mathcal K\) let \(\text{Con}_{{\mathcal K}} A\) be the lattice of all congruence relations \(\theta\) on \(A\) such that \(A/\theta\in {\mathcal K}\). Define the embedding relation \(\leq\) as follows: \(\theta\leq \theta'\) iff \(A/\theta'\) is embeddable into \(A/\theta\).
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Quasivarieties and Varieties of Lattice-Ordered Groups

1996
Many properties and statements of the theory of lattice-ordered groups (l-groups) can be formulated and proved in terms of first order logic. Special mention should be made of properties expressed by universal sentences such as identities and implications, which can be referred to as the theory of varieties and quasivarieties, respectively, of l-groups.
V. M. Kopytov, N. Ya. Medvedev
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The Lattice of Quasivarieties of Torsion-Free Metabelian Groups

Algebra and Logic, 2003
Let \(M\) be a quasivariety and let \(L_q(M)\) be the lattice of quasivarieties in \(M\). The author denotes by \(F_2(A^2)\) a free metabelian group on two generators and by \(F_2(N_2)\) a free nilpotent group of degree two on two generators. Theorem 2.
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