A characterization of congruence classes of quasigroups
A characterization of distributive lattices by tolerance lattices
A characterization of polarities whose lattice of polars is Boolean
A characterization of the group congruences on a semigroup.
A characterization of tolerance-distributive tree semilattices
A common generalization of permutability and 0-permutability
A contribution to the theory of decompositions of partial algebras
A factorization of quasiorder hypergroups
The contribution is devoted to the question of the interchange of the construction of a quasiorder hypergroup from a quasiordered set and the factorization.
A generalization of equivalence relations.
A lattice of homomorphs
A note on idempotent separating congruences on a regular semigroup
A note on subdirectly irreducible groupoids
A note on the finite extensivity property
A note on the strongly compatible tolerances on an arbitrary semigroup
A note on tolerance lattices
A note on tolerance lattices of algebras with restricted similarity type
A note on triangular schemes for weak congruences
Some geometrical methods, the so called Triangular Schemes and Principles, are introduced and investigated for weak congruences of algebras. They are analogues of the corresponding notions for congruences. Particular versions of Triangular Schemes are equivalent to weak congruence modularity and to weak congruence distributivity. For algebras in congruence permutable varieties, stronger properties—Triangular Principles—are equivalent to weak congruence modularity and distributivity.
A note on varieties with distributive subalgebra lattices
A regular a-semigroups inducing a certain lattice.
A remark on polynomial functions over finite monoids.