Demi-groupes présimplifiables
Dense extensions of completely 0-simple semigroups. I.
Dense extensions of completely 0-simple semigroups. II.
Dense subsets of some common classes of semigroups.
Des schémas en demi-groupes commutatifs.
Describing uniform bands in terms of uniform semilattices.
Die Darstellung von partiellen -stelligen Operationen
Die Halbgruppen der Ordnungen = <7 .
Die -abgeschlossenen Teilmengen der Halbgruppen
Die...-Klassen der endlichen symmetrischen Halbgruppen und ihre Mächtigkeiten.
Differences in sets of lengths of Krull monoids with finite class group
Let be a Krull monoid with finite class group where every class contains some prime divisor. It is known that every set of lengths is an almost arithmetical multiprogression. We investigate which integers occur as differences of these progressions. In particular, we obtain upper bounds for the size of these differences. Then, we apply these results to show that, apart from one known exception, two elementary -groups have the same system of sets of lengths if and only if they are isomorphic.
Differentiability of a convex semigroup on IRm.
Direct decomposability of tolerances and congruences on semigroups
Direct products of cyclic semigroups admitting a planar Cayley graph.
Direct products of cyclic semigroups and unions of groups.
Discrete semigroups in nilpotent Lie groups.
Disjunctive languages and compatible orders
Disjunctive splittability of languages.
Disjunktive Teilmengen inverser Halbgruppen
Distance desert automata and the star height problem
We introduce the notion of nested distance desert automata as a joint generalization of distance automata and desert automata. We show that limitedness of nested distance desert automata is PSPACE-complete. As an application, we show that it is decidable in space whether the language accepted by an -state non-deterministic automaton is of a star height less than a given integer (concerning rational expressions with union, concatenation and iteration), which is the first ever complexity bound...