On subdirectly irreducible lattice-ordered semigroups .
On the lattice of completely regular monoid varieties.
On the lattice of torsion classes of lattice ordered groups
On the lattice of varieties of completely simple semigroups.
On the Pin-Thérien expansion of idempotent monoids.
On the quasivarieties generated by finite semigroups.
On the solidity of general varieties of tree languages
For a class of hypersubstitutions 𝓚, we define the 𝓚-solidity of general varieties of tree languages (GVTLs) that contain tree languages over all alphabets, general varieties of finite algebras (GVFAs), and general varieties of finite congruences (GVFCs). We show that if 𝓚 is a so-called category of substitutions, a GVTL is 𝓚-solid exactly in case the corresponding GVFA, or the corresponding GVFC, is 𝓚-solid. We establish the solidity status of several known GVTLs with respect to certain categories...
On the Specht property of varieties of commutative alternative algebras over a field of characteristic 3 and commutative Moufang loops.
On the varieties of Cliffordian Semigroups.
On the varieties of completely regular semigroups.
On two classes of hereditarily finitely based semigroup identities.
On universality of semigroup varieties
A category is called -determined if every set of non-isomorphic -objects such that their endomorphism monoids are isomorphic has a cardinality less than . A quasivariety is called -universal if the lattice of all subquasivarieties of any quasivariety of finite type is a homomorphic image of a sublattice of the lattice of all subquasivarieties of . We say that a variety is var-relatively alg-universal if there exists a proper subvariety of such that homomorphisms of whose image does...
On varieties generated by Boolean clones.
On varieties of combinatorial inverse semigroups I.
On varieties of combinatorial inverse semigroups II.
On varieties of completely regular semigroups.
On varieties of completely regular semigroups II.
On varieties of completely regular semigroups III.
On varieties of graphs
In this paper, we introduce the notion of a variety of graphs closed under isomorphic images, subgraph identifications and induced subgraphs (induced connected subgraphs) firstly and next closed under isomorphic images, subgraph identifications, circuits and cliques. The structure of the corresponding lattices is investigated.
On varieties of left distributive left idempotent groupoids
We describe a part of the lattice of subvarieties of left distributive left idempotent groupoids (i.e. those satisfying the identities x(yz) ≈ (xy)(xz) and (xx)y ≈ xy) modulo the lattice of subvarieties of left distributive idempotent groupoids. A free groupoid in a subvariety of LDLI groupoids satisfying an identity xⁿ ≈ x decomposes as the direct product of its largest idempotent factor and a cycle. Some properties of subdirectly ireducible LDLI groupoids are found.