Marianne Johnson

collaborators

6 papers

math.GR2026

The endomorphism tower of a finite symmetric group

Victoria Gould, Ambroise Grau, Marianne Johnson +1

We consider the endomorphism tower of a monoid $M$ , that is, the sequence of monoids End $_{i} (M)$ where End $_{0} (M) = M$ and for all $i \geq 1$ , End $_{i} (M)$ is the monoid of all endomorphi…

math.RA2025

Subset expansions of monoids

Victoria Gould, Marianne Johnson

We initiate the study of the expansion $S (M)$ of a monoid $M$ obtained via the semidirect product of $M$ acting naturally on the left of its power set (regarded as a semi…

math.RA2025

A new approach to the grammic monoid

Marianne Johnson, AntÃ³nio Malheiro

We give an alternative description of the grammic monoid in terms of weakly increasing subsequences. Specifically, we show that words $u, v$ in the generators ${1, \dots, n}$ dete…

math.GR2025

Free inverse monoids are co-context-free

Tara Macalister Brough, Marianne Johnson, Mark Kambites +1

We prove (using grammars) that the free inverse monoid of every finite rank has co-context-free word problem. Equivalently, the co-word problem of the free inverse monoid of every…

cs.FL2025

Feasability of Learning Weighted Automata on a Semiring

Laure Daviaud, Marianne Johnson

Since the seminal work by Angluin and the introduction of the L*-algorithm, active learning of automata by membership and equivalence queries has been extensively studied to learn…

math.RA2025

Forbidden configurations for coherency

Victoria Gould, Marianne Johnson

Right (and left) coherency and right (and left) weak coherency are natural finitary conditions for monoids. Determining whether or not a given monoid has any of these properties is…