E-free objects and E-locality for completely regular semigroups.
Embedding semigroups in groups. A geometrical approach.
Embedding sums of cancellative modes into semimodules
A mode (idempotent and entropic algebra) is a Lallement sum of its cancellative submodes over a normal band if it has a congruence with a normal band quotient and cancellative congruence classes. We show that such a sum embeds as a subreduct into a semimodule over a certain ring, and discuss some consequences of this fact. The result generalizes a similar earlier result of the authors proved in the case when the normal band is a semilattice.
Equationally compact algebras (I)
Equationally compact algebras II
Equationally compact algebras (III)
Equations on the semidirect product of a finite semilattice by a finite commutative monoid.
Equimorphy in varieties of double Heyting algebras
We show that any finitely generated variety V of double Heyting algebras is finitely determined, meaning that for some finite cardinal n(V), any class ⊆ V consisting of algebras with pairwise isomorphic endomorphism monoids has fewer than n(V) pairwise non-isomorphic members. This result complements the earlier established fact of categorical universality of the variety of all double Heyting algebras, and contrasts with categorical results concerning finitely generated varieties of distributive...
Errata for the paper "Equationally compact algebras II" (Fundamenta Mathematica 61 (1968), pp. 271-281)
Exponentiality in categories of partial algebras.