Nil-extensions of unions of groups induced by identities.
Nilpotents in semigroups of partial one-to-one order-preserving mappings.
Noncommutative analogs of symmetric polynomials
Nonsymmetric group algebras
Normal forms for band free products.
Note on compatible well orders on a free monoid.
Notes on semimedial semigroups
The class of semigroups satisfying semimedial laws is studied. These semigroups are called semimedial semigroups. A connection between semimedial semigroups, trimedial semigroups and exponential semigroups is presented. It is proved that the class of strongly semimedial semigroups coincides with the class of trimedial semigroups and the class of dimedial semigroups is identical with the class of exponential semigroups.
Notion de demi-bande : demi-bande de type deux.
Numerical semigroups with a monotonic Apéry set
We study numerical semigroups with the property that if is the multiplicity of and is the least element of congruent with modulo , then . The set of numerical semigroups with this property and fixed multiplicity is bijective with an affine semigroup and consequently it can be described by a finite set of parameters. Invariants like the gender, type, embedding dimension and Frobenius number are computed for several families of this kind of numerical semigroups.