All a b c d e f g h i j k l m n o p q r s t u v w x y z Other

Previous Page 51 Next

Displaying 1001 – 1020 of 1398

Showing per page

Small idempotent clones. I

Józef Dudek (1998)

Czechoslovak Mathematical Journal

G. Grätzer and A. Kisielewicz devoted one section of their survey paper concerning p n -sequences and free spectra of algebras to the topic “Small idempotent clones” (see Section 6 of [18]). Many authors, e.g., [8], [14, 15], [22], [25] and [29, 30] were interested in p n -sequences of idempotent algebras with small rates of growth. In this paper we continue this topic and characterize all idempotent groupoids ( G , · ) with p 2 ( G , · ) ≤ 2 (see Section 7). Such groupoids appear in many papers see, e.g. [1], [4], [21], [26,...

Solving systems of two–sided (max, min)–linear equations

Martin Gavalec, Karel Zimmermann (2010)

Kybernetika

A finite iteration method for solving systems of (max, min)-linear equations is presented. The systems have variables on both sides of the equations. The algorithm has polynomial complexity and may be extended to wider classes of equations with a similar structure.

Some decidable congruences of free monoids

Jaroslav Ježek (1999)

Czechoslovak Mathematical Journal

Let W be the free monoid over a finite alphabet A . We prove that a congruence of W generated by a finite number of pairs 〈 a u , u 〉 , where a ∈ A and u ∈ W , is always decidable.

Some modifications of congruence permutability and dually congruence regular varietie

Ivan Chajda, Günther Eigenthaler (2001)

Discussiones Mathematicae - General Algebra and Applications

It is well known that every congruence regular variety is n-permutable (in the sense of [9]) for some n ≥ 2. For the explicit proof see e.g. [2]. The connections between this n and Mal'cev type characterizations of congruence regularity were studied by G.D. Barbour and J.G. Raftery [1]. The concept of local congruence regularity was introduced in [3]. A common generalization of congruence regularity and local congruence regularity was given in [6] under the name "dual congruence regularity with...

Some monounary algebras with EKP

Emília Halušková (2020)

Mathematica Bohemica

An algebra 𝒜 is said to have the endomorphism kernel property (EKP) if every congruence on 𝒜 is the kernel of some endomorphism of 𝒜 . Three classes of monounary algebras are dealt with. For these classes, all monounary algebras with EKP are described.

Some properties of residuated lattices

Radim Bělohlávek (2003)

Czechoslovak Mathematical Journal

We investigate some (universal algebraic) properties of residuated lattices—algebras which play the role of structures of truth values of various systems of fuzzy logic.

Some properties of the weak subalgebra lattice of a partial algebra of a fixed type

Konrad Pióro (2002)

Archivum Mathematicum

We investigate, using results from [[p3]], when a given lattice is isomorphic to the weak subalgebra lattice of a partial algebra of a fixed type. First, we reduce this problem to the question when hyperedges of a hypergraph can be directed to a form of directed hypergraph of a fixed type. Secondly, we show that it is enough to consider some special hypergraphs. Finally, translating these results onto the lattice language, we obtain necessary conditions for our algebraic problem, and also, we completely...

Some regular quasivarieties of commutative binary modes

K. Matczak, Anna B. Romanowska (2014)

Commentationes Mathematicae Universitatis Carolinae

Irregular (quasi)varieties of groupoids are (quasi)varieties that do not contain semilattices. The regularization of a (strongly) irregular variety 𝒱 of groupoids is the smallest variety containing 𝒱 and the variety 𝒮 of semilattices. Its quasiregularization is the smallest quasivariety containing 𝒱 and 𝒮 . In an earlier paper the authors described the lattice of quasivarieties of cancellative commutative binary modes, i.e. idempotent commutative and entropic (or medial) groupoids. They are all irregular...

Currently displaying 1001 – 1020 of 1398