Atomicity and density of Puiseux monoids

Identifier:  imarina:9138872

Handle: https://hdl.handle.net/20.500.11797/imarina9138872

Authors:  Bras-Amoros, Maria; Gotti, Marly

Abstract:
© 2020 Taylor & Francis Group, LLC. A Puiseux monoid is an additive submonoid consisting of non-negative rationals. Although the operation of addition is continuous with respect to the standard topology, the set of irreducibles of a Puiseux monoid is, in general, difficult to describe. Here, we use topological density to understand how much a Puiseux monoid, as well as its set of irreducibles, spread throughout the real line. First, we separate Puiseux monoids according to their density, and we characterize monoids in each of these classes in terms of generating sets and sets of irreducibles. Then we study the density of the difference group, the root closure, and the conductor semigroup of a Puiseux monoid. Finally, we prove that every Puiseux monoid generated by a strictly increasing sequence of rationals is nowhere dense in the real line and has empty conductor.