The 0-distributivity in the class of subalgebra lattices of Heyting algebras and closure algebras
The a-congruences on S(X) and the S-equivalences on X.
The amalgamation basis of the category of compact groups.
The concept of structural regularity.
The congruence extension property for algebraic semigroups.
The congruence lattice of implication algebras.
The Csákány theory of regularity for finite algebras
The degrees of regularity in varieties
The egg-box property of congruences
The monoid of strong endomorphisms of a graph.
The one-block property in varieties of semigroups.
The Rees Congruence in Universal Algebras
The semigroup generated by certain operators on the congruence lattice of a Clifford semigroup.
The structure of commutative ideal semigroups.
The subalgebra lattice of a finite algebra
The aim of this paper is to characterize pairs (L, A), where L is a finite lattice and A a finite algebra, such that the subalgebra lattice of A is isomorphic to L. Next, necessary and sufficient conditions are found for pairs of finite algebras (of possibly distinct types) to have isomorphic subalgebra lattices. Both of these characterizations are particularly simple in the case of distributive subalgebra lattices. We do not restrict our attention to total algebras only, but we consider the more...
The subalgebra lattice of a Heyting algebra
The variety generated by tournaments
The weak subalgebra lattice of a unary partial algebra of a given infinite unary type
Tolerance distributive and tolerance Boolean varieties of semigroups
Tolerance distributive and tolerance modular varieties of commutative semigroups