Die Darstellung von partiellen -stelligen Operationen
Die Einbettung von Mittelwertstrukturen in Q-Vektorräume.
Die subdirekte Unzerlegbarkeit der Intervallrechnung.
Die Verbände mit nichteinfacher Funktionenalgebra.
Different levels of word problems for some varieties.
Dimension theory for cyclically and cocyclically ordered sets
Direct decomposability of congruences in congruence-permutable varieties
Direct decomposability of tolerances and congruences on semigroups
Direct decomposability of tolerances on lattices, semilattices and quasilattices
Direct limits of congruence systems
Direct limits of monounary algebras
Direct products of homomorphic mappings. I
Direct products of homomorphic mappings. II
Direct products of weak homomorphisms
Directable automata and their generalizations: A survey.
Directly decomposable congruences in varieties with nullary operations
Directly decomposable tolerances on direct products of lattices and semilattices
Directoid groups
We continue the study of directoid groups, directed abelian groups equipped with an extra binary operation which assigns an upper bound to each ordered pair subject to some natural restrictions. The class of all such structures can to some extent be viewed as an equationally defined substitute for the class of (2-torsion-free) directed abelian groups. We explore the relationship between the two associated categories, and some aspects of ideals of directoid groups.
Discriminator order algebras
We prove that an order algebra assigned to a bounded poset with involution is a discriminator algebra.
Discriminator varieties of Boolean algebras with residuated operators
The theory of discriminator algebras and varieties has been investigated extensively, and provides us with a wealth of information and techniques applicable to specific examples of such algebras and varieties. Here we give several such examples for Boolean algebras with a residuated binary operator, abbreviated as r-algebras. More specifically, we show that all finite r-algebras, all integral r-algebras, all unital r-algebras with finitely many elements below the unit, and all commutative residuated...