Semidirectly closed pseudovarieties of locally trivial semigroups.
Simple and subdirectly irreducibles bounded distributive lattices with unary operators.
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.
Subdirect decompositions of algebras from 2-clone extensions of varieties
Let τ:F → ℕ be a type of algebras, where F is a set of fundamental operation symbols and ℕ is the set of nonnegative integers. We assume that |F|≥2 and 0 ∉ (F). For a term φ of type τ we denote by F(φ) the set of fundamental operation symbols from F occurring in φ. An identity φ ≉ ψ of type τ is called clone compatible if φ and ψ are the same variable or F(φ)=F(ψ)≠. For a variety V of type τ we denote by the variety of type τ defined by all identities φ ≉ ψ from Id(V) which are either clone compatible...
Subdirect products of certain varieties of unary algebras
J. Płonka in [12] noted that one could expect that the regularization of a variety of unary algebras is a subdirect product of and the variety of all discrete algebras (unary semilattices), but is not the case. The purpose of this note is to show that his expectation is fulfilled for those and only those irregular varieties which are contained in the generalized variety of the so-called trap-directable algebras.
Subdirectly irreducible algebras of quasiordered logics
Subdirectly irreducible decomposition of some algebras having the semilattice structure
Subdirectly irreducible semilattices with an automorphism.
Subdirectly Irreducibles in some Varieties of Algebras having the Semilattice Structure
Subdirekte Produkte und konjunkte Summen.