-Lattices of varieties of algebras of different types
Valuations of structures
Varieties and finite closure conditions
Varieties generated by free completely simple semigroups.
Varieties generated by two-element majority algebras and their equivalences
Varieties having directly decomposable congruence classes
Varieties having distributive lattices of quasiorders
Varieties having the congruence extension property
Varieties of abelian quasigroups
Varieties of algebras with equationally definable zeros
Varieties of an enriched category
Varieties of associative rings closed under ideal sums
Varieties of completely regular semigroups generated by Mal'cev products.
Varieties of distributive lattices with unary operations. II.
Varieties of Distributive Rotational Lattices
A rotational lattice is a structure where is a lattice and is a lattice automorphism of finite order. We describe the subdirectly irreducible distributive rotational lattices. Using Jónsson’s lemma, this leads to a description of all varieties of distributive rotational lattices.
Varieties of finite categories
Varieties of groupoids determined by short linear identities
Varieties of idempotent groupoids with small clones
We give an equational description of all idempotent groupoids with at most three essentially n-ary term operations.
Varieties of idempotent medial n-quasigroups
Varieties of idempotent slim groupoids
Idempotent slim groupoids are groupoids satisfying and . We prove that the variety of idempotent slim groupoids has uncountably many subvarieties. We find a four-element, inherently nonfinitely based idempotent slim groupoid; the variety generated by this groupoid has only finitely many subvarieties. We investigate free objects in some varieties of idempotent slim groupoids determined by permutational equations.