Special congruence triples for a regular semigroup.
Special incidence structures of type
Special incidence structures of type . II.
Special m-hyperidentities in biregular leftmost graph varieties of type (2,0)
Graph algebras establish a connection between directed graphs without multiple edges and special universal algebras of type (2,0). We say that a graph G satisfies a term equation s ≈ t if the corresponding graph algebra satisfies s ≈ t. A class of graph algebras V is called a graph variety if where Σ is a subset of T(X) × T(X). A graph variety is called a biregular leftmost graph variety if Σ’ is a set of biregular leftmost term equations. A term equation s ≈ t is called an identity in a variety...
Special types of universal algebras preserving a relation
Split extensions and semidirect products of unitary magmas
We develop a theory of split extensions of unitary magmas, which includes defining such extensions and describing them via suitably defined semidirect product, yielding an equivalence between the categories of split extensions and of (suitably defined) actions of unitary magmas on unitary magmas. The class of split extensions is pullback stable but not closed under composition. We introduce two subclasses of it that have both of these properties.
Standard cohomology of semigroups
Statistical linear spaces. I. Properties of , -topology
Statistical linear spaces. II. Strongest -norm
Strict refinement for direct sums and graphs.
Strictly order primal algebras.
Strong amalgamations of lattice ordered groups and modules.
Strong embedding of category of all groupoids into category of semigroups
Strong endomorphism kernel property for finite Brouwerian semilattices and relative Stone algebras
We show that all finite Brouwerian semilattices have strong endomorphism kernel property (SEKP), give a new proof that all finite relative Stone algebras have SEKP and also fully characterize dual generalized Boolean algebras which possess SEKP.
Strong endomorphism kernel property for monounary algebras
All monounary algebras which have strong endomorphism kernel property are described.
Strong P-congruences on P-regular semigroups.
Strong regular varieties of partial algebras I
Strong retracts of unary algebras
This paper introduces the notion of a strong retract of an algebra and then focuses on strong retracts of unary algebras. We characterize subuniverses of a unary algebra which are carriers of its strong retracts. This characterization enables us to describe the poset of strong retracts of a unary algebra under inclusion. Since this poset is not necessarily a lattice, we give a necessary and sufficient condition for the poset to be a lattice, as well as the full description of the poset.
Structure of free algebras
Structures Algebraiques munis, avec des lois de composition generalisees - Generalisations du produit scalaire