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Displaying 61 – 80 of 229

Directly decomposable congruences in varieties with nullary operations

Ivan Chajda (1987)

Mathematica Slovaca

Distributed families of varieties of algebras

Jerzy Plonka (1987)

Beiträge zur Algebra und Geometrie = Contributions to algebra and geometry

Distributive multisemilattices [Book]

Arthur Knoebel, Anna Romanowska (1991)

Equational bases for weak monounary varieties

Grzegorz Bińczak (2002)

Discussiones Mathematicae - General Algebra and Applications

It is well-known that every monounary variety of total algebras has one-element equational basis (see [5]). In my paper I prove that every monounary weak variety has at most 3-element equational basis. I give an example of monounary weak variety having 3-element equational basis, which has no 2-element equational basis.

Equational theories of some almost unary groupoids

Jaroslav Ježek (1986)

Commentationes Mathematicae Universitatis Carolinae

Even equations and Agassiz sums

Jacek Kuras (1987)

Colloquium Mathematicae

Every at most four element algebra has a Mal'cev theory for permutability

Ivan Chajda (1991)

Mathematica Slovaca

Factorable congruences and factorable congruence blocks on powers of a finite algebra

Jaromír Duda (1992)

Czechoslovak Mathematical Journal

Finite basis theorem for systems of semigroup identities.

M.V. Volkov (1984)

Semigroup forum

Finitely axiomatizable varieties of BCK-algebras.

B. Wozniakowska (1985)

Semigroup forum

Finitely generated relations and their applications to permutable and $n$ -permutable varieties

Ivan Chajda, Jaromír Duda (1982)

Commentationes Mathematicae Universitatis Carolinae

Frattini theory for classes of finite universal algebras of Mal'tsev varieties.

Guo, Wenbin, Shum, Kar-Ping (2002)

Sibirskij Matematicheskij Zhurnal

Free Abelian extensions in the congruence-permutable varieties

Pavel Zhdanovich (2002)

Discussiones Mathematicae - General Algebra and Applications

We obtain the construction of free abelian extensions in a congurence-permutable variety V using the construction of a free abelian extension in a variety of algebras with one ternary Mal'cevoperation and a monoid of unary operations. We also use this construction to obtain a free solvable V-algebra.

Free systems of algebras and ultraclosed classes.

Thron, R., Koppitz, J. (2006)

Acta Mathematica Universitatis Comenianae. New Series

Galois theory and double central extensions.

Gran, Marino, Rossi, Valentina (2004)

Homology, Homotopy and Applications

Generalization of the concept of variety and quasivariety to partial algebras through category theory [Book]

H. Andréka, I. Németi (1983)

Generalized deductive systems in subregular varieties

Ivan Chajda (2003)

Mathematica Bohemica

An algebra $𝒜 = (A, F)$ is subregular alias regular with respect to a unary term function $g$ if for each $Θ, Φ \in Con 𝒜$ we have $Θ = Φ$ whenever ${[g (a)]}_{Θ} = {[g (a)]}_{Φ}$ for each $a \in A$ . We borrow the concept of a deductive system from logic to modify it for subregular algebras. Using it we show that a subset $C \subseteq A$ is a class of some congruence on $Θ$ containing $g (a)$ if and only if $C$ is this generalized deductive system. This method is efficient (needs a finite number of steps).

Currently displaying 61 – 80 of 229