Results 271 to 280 of about 6,883 (313)

Studying semigroups of mappings using quasi-identities

Semigroup Forum, 2001
A \(pq\)-variety \(V\) is a class of finite semigroups closed under the formation of subsemigroups and finitary direct products; (equivalently \(V\) is defined by a set of quasi-identities, that is identities that are formal consequences of a list of other identities. For example, left cancellativity: \((xy=xz\to y=z)\)).
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On quasi-identities of relation algebras with diophantine operations

Siberian Mathematical Journal, 1997
Let \(\operatorname{Rel}(U)\) denote the set of all binary relations defined on a set \(U\). Consider the set of operations \(F_{\varphi}(r_{1}, \ldots, r_{n}) = (x, y)\), where \(\varphi(x, y, r_{1}, \ldots, r_{n})\) is valid in \(U\) on elements \(x, y\) and relations \(r_{1}, \ldots, r_{n}\). A set of relations \(\Phi \subseteq \operatorname{Rel}(U)\
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Bayesian approach to proof loading of quasi-identical multi-components structural systems

Civil Engineering and Environmental Systems, 2007
The present article considers a special class of structural systems for which condition control has proven to constitute a real problem, namely attachments such as e.g., fasteners of facade systems, anchors of retaining walls, rivets in riveted connections, riser attachments of offshore platforms, and many other similar types of structures.
K. Nishijima, M. H. Faber
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A single quasi-identity for a quasivariety with the Fraser-Horn property

Algebra Universalis, 1992
A quasivariety \(\mathbb{K}\) is said to be finitely axiomatizable relative to \(H(\mathbb{K})\) if there exists a finite set \(\Sigma\) of quasi-identities such that for all \(A\) of \(H(\mathbb{K})\), \(A\in\mathbb{K}\) iff \(A\) satisfies each quasi- identity of \(\Sigma\) (or equivalently, \(\mathbb{K}=\text{Mod(Id}(\mathbb{K})\cup\Sigma)\), where \
Czelakowski, Janusz, Dziobiak, Wiesław
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Quasi-identities of a free 2-nilpotent group

Mathematical Notes of the Academy of Sciences of the USSR, 1986
Translation from Mat. Zametki 40, No.5, 590-597 (Russian) (1986; Zbl 0617.20013).
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On quasi-identities of finitely generated commutative Moufang loops

Algebra and Logic, 1991
\textit{T. Evans} [J. Algebra 31, 508-513 (1974; Zbl 0285.20058)] proved that each finitely generated commutative Moufang loop has a finite basis of identities. This paper now aims at describing the finitely generated commutative Moufang loops with a finite basis of quasi-identities. First, the author adapts the group-theoretic method of \textit{A. Yu.
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Geometric scales for varieties of algebras and quasi-identities

Siberian Advances in Mathematics, 2010
Summary: We introduce a preorder for universal algebras with respect to their geometries. This naturally leads to the notion of the geometric scale for a variety of algebras. We investigate connections between the introduced relation and infinite quasi-identities that hold in algebras, as well as other properties of the relation and the scale.
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Checking quasi-identities in a finite semigroup may be computationally hard

Studia Logica, 2004
Many basic questions in algebra turn out to be (computationally) surprisingly difficult. For instance, it was shown by \textit{C. Bergman} and \textit{G. Slutzki} [SIAM J. Comput. 30, No. 2, 359-382 (2000; Zbl 0963.68077)] that the question of whether two finite algebras satisfy the same quasi-identities is NP-complete.
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AN INDEPENDENT BASIS FOR THE QUASI-IDENTITIES OF A FREE CANTOR ALGEBRA

Mathematics of the USSR-Sbornik, 1975
Let be the minimal quasi-variety contained in the variety of Cantor algebras. It is shown that the set of quasi-identities of the quasi-variety possesses an independent basis.Bibliography: 6 titles.
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On the Quasivarieties Generated by a Finite Group and Lacking Any Independent Bases of Quasi-Identities

Siberian Mathematical Journal, 2020
zbMATH Open Web Interface contents unavailable due to conflicting licenses.
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