Undecidable varieties with solvable word problems. II.
Undecidable varieties with solvable word problems. III (a semigroup variety).
Une approche transformationelle à l'algèbre universelle.
Une extension du lemme de Green et ses applications
Uniformity of congruences in coherent varieties
An algebra is uniform if for each , every two classes of have the same cardinality. It was shown by W. Taylor that coherent varieties need not be uniform (and vice versa). We show that every coherent variety having transferable congruences is uniform.
Union and symmetry preserving homomorphisms of semigroups of closed relations.
Uniqueness of improper operations
Universal algebras with all operations of bounded range
Universal cyclic relations
Universal cyclically ordered sets
Univerzální algebry
Unsolid and fluid strong varieties of partial algebras.
Upper and Lower Bounds in Relator Spaces
2000 Mathematics Subject Classification: 06A06, 54E15An ordered pair X(R) = ( X, R ) consisting of a nonvoid set X and a nonvoid family R of binary relations on X is called a relator space. Relator spaces are straightforward generalizations not only of uniform spaces, but also of ordered sets. Therefore, in a relator space we can naturally define not only some topological notions, but also some order theoretic ones. It turns out that these two, apparently quite different, types of notions are closely...
Užití zobecněné věty Jordan-Hölderovy v teorii direktních součinů množin s operátory
Valuations of structures
Varieties generated by two-element majority algebras and their equivalences
Varieties having directly decomposable congruence classes
Varieties of distributive lattices with unary operations. II.
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