-systems of unary algebras. I: On maximal and greatest -classes of the direct product of unary algebras
-systems of unary algebras. II: Maximal and minimal subalgebras of the direct products of unary algebras
Radical decompositions of semiheaps
Semiheaps are ternary generalisations of involuted semigroups. The first kind of semiheaps studied were heaps, which correspond closely to groups. We apply the radical theory of varieties of idempotent algebras to varieties of idempotent semiheaps. The class of heaps is shown to be a radical class, as are two larger classes having no involuted semigroup counterparts. Radical decompositions of various classes of idempotent semiheaps are given. The results are applied to involuted I-semigroups, leading...
Radicals and their left ideal analogues in a semigroup
Radicals commuting with bands of semigroups.
Radicals in Quasi-Commutative Semigroups
Radicals in semigroups.
Radicals of Green’s relations
Some structural descriptions of semigroups in which the radicals of Green’s relations are semilattice congruences will be given.
Radicals of semi-group rings
Radicals of semigroup rings of commutative semigroups.
Radicals of semigroup rings of orthogroups.
Radicals of semigroups.
Range sets and partition sets in connection with congruences and algebraic invariants.
Ranks of binary relations.
Rational strong codes and structure of rational group languages.
Rational tree morphisms and transducer integer sequences: definition and examples.
RC-commutative ...-semigroups.
Realization theorems for semigroups with divisor theory.
Recent developments in the theory of skew lattices.
Rechtskomplementäre Halbgruppen, Axiome, Polynome, Kongruenzen.