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Characterizing binary discriminator algebras

Ivan Chajda (2000)

Mathematica Bohemica

The concept of the (dual) binary discriminator was introduced by R. Halas, I. G. Rosenberg and the author in 1999. We study finite algebras having the (dual) discriminator as a term function. In particular, a simple characterization is obtained for such algebras with a majority term function.

Characterizing matrices with 𝐗 -simple image eigenspace in max-min semiring

Ján Plavka, Sergeĭ Sergeev (2016)

Kybernetika

A matrix A is said to have 𝐗 -simple image eigenspace if any eigenvector x belonging to the interval 𝐗 = { x : x ̲ ≤ x ≤ x ¯ } is the unique solution of the system A ⊗ y = x in 𝐗 . The main result of this paper is a combinatorial characterization of such matrices in the linear algebra over max-min (fuzzy) semiring. The characterized property is related to and motivated by the general development of tropical linear algebra and interval analysis, as well as the notions of simple image set and weak robustness (or weak stability) that...

Characterizing pure, cryptic and Clifford inverse semigroups

Mario Petrich (2014)

Czechoslovak Mathematical Journal

An inverse semigroup S is pure if e = e 2 , a ∈ S , e < a implies a 2 = a ; it is cryptic if Green’s relation ℋ on S is a congruence; it is a Clifford semigroup if it is a semillatice of groups. We characterize the pure ones by the absence of certain subsemigroups and a homomorphism from a concrete semigroup, and determine minimal nonpure varieties. Next we characterize the cryptic ones in terms of their group elements and also by a homomorphism of a semigroup constructed in the paper. We also characterize groups and...

Characterizing tolerance trivial finite algebras

Ivan Chajda (1994)

Archivum Mathematicum

An algebra A is tolerance trivial if A ̰ = A where A ̰ is the lattice of all tolerances on A . If A contains a Mal’cev function compatible with each T A ̰ , then A is tolerance trivial. We investigate finite algebras satisfying also the converse statement.

Class preserving mappings of equivalence systems

Ivan Chajda (2004)

Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica

By an equivalence system is meant a couple 𝒜 = ( A , θ ) where A is a non-void set and θ is an equivalence on A . A mapping h of an equivalence system 𝒜 into ℬ is called a class preserving mapping if h ( [ a ] θ ) = [ h ( a ) ] θ ' for each a ∈ A . We will characterize class preserving mappings by means of permutability of θ with the equivalence Φ h induced by h .

Clausal relations and C-clones

Edith Vargas (2010)

Discussiones Mathematicae - General Algebra and Applications

We introduce a special set of relations called clausal relations. We study a Galois connection Pol-CInv between the set of all finitary operations on a finite set D and the set of clausal relations, which is a restricted version of the Galois connection Pol-Inv. We define C-clones as the Galois closed sets of operations with respect to Pol-CInv and describe the lattice of all C-clones for the Boolean case D = {0,1}. Finally we prove certain results about C-clones over a larger set.

Clifford congruences on generalized quasi-orthodox GV-semigroups

Sunil K. Maity (2013)

Discussiones Mathematicae - General Algebra and Applications

A semigroup S is said to be completely π-regular if for any a ∈ S there exists a positive integer n such that aⁿ is completely regular. A completely π-regular semigroup S is said to be a GV-semigroup if all the regular elements of S are completely regular. The present paper is devoted to the study of generalized quasi-orthodox GV-semigroups and least Clifford congruences on them.

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