Congruence relations on direct products of lattices
Congruence relations on finitary models
Congruence restrictions on axes
We give Mal’cev conditions for varieties 4V4 whose congruences on the product , are determined by their restrictions on the axes in .
Congruence schemes and their applications
Using congruence schemes we formulate new characterizations of congruence distributive, arithmetical and majority algebras. We prove new properties of the tolerance lattice and of the lattice of compatible reflexive relations of a majority algebra and generalize earlier results of H.-J. Bandelt, G. Cz'{e}dli and the present authors. Algebras whose congruence lattices satisfy certain 0-conditions are also studied.
Congruence semimodularity of conservative groupoids
Congruence submodularity
We present a countable infinite chain of conditions which are essentially weaker then congruence modularity (with exception of first two). For varieties of algebras, the third of these conditions, the so called 4-submodularity, is equivalent to congruence modularity. This is not true for single algebras in general. These conditions are characterized by Maltsev type conditions.
Congruence Topologies on Universal Algebras.
Congruences and ideals in ternary rings
A ternary ring is an algebraic structure of type satisfying the identities and where, moreover, for any , , there exists a unique with . A congruence on is called normal if is a ternary ring again. We describe basic properties of the lattice of all normal congruences on and establish connections between ideals (introduced earlier by the third author) and congruence kernels.
Congruences and ideals on left divisible involutory groupoids
In [1] ideals and congruences on semiloops were investigated. The aim of this paper is to generalize results obtained for semiloops to the case of left divisible involutory groupoids.
Congruences associated with inverse transversals.
Congruences generated by filters
Congruences of pseudocomplemented algebras
Congruences on an inverse Bruck-Reilly monoid. Part I: Non-group congruences.
Congruences on bands of π-groups
A semigroup S is said to be completely π-regular if for any a ∈ S there exists a positive integer n such that aⁿ is completely regular. The present paper is devoted to the study of completely regular semigroup congruences on bands of π-groups.
Congruences on Bruck-Reilly extensions of monoids.
Congruences on products in varieties satisfying the CEP
Congruences on semilattices with section antitone involutions
We deal with congruences on semilattices with section antitone involution which rise e.g., as implication reducts of Boolean algebras, MV-algebras or basic algebras and which are included among implication algebras, orthoimplication algebras etc. We characterize congruences by their kernels which coincide with semilattice filters satisfying certain natural conditions. We prove that these algebras are congruence distributive and 3-permutable.
Congruences on the subclones of the rank 3 Burle clone containing no creative functions.
Constructions of (2,n)-varieties of groupoids for n = 7, 8, 9
Convex sets in algebras