4 papers
The Inverse Monoid of Partial Inner Automorphisms of a Semigroup
João Araújo, Wolfram Bentz, Michael Kinyon +2
We introduce the inverse monoid of inner partial automorphisms of a semigroup -- a tool that associates to every semigroup an inverse semigroup. When the semigroup is a group, this…
Conjugacy in Abstract Semigroups, Transformation and Diagram Monoids, and Conjugacy Growth
João Araújo, Wolfram Bentz, Michael Kinyon +3
We study conjugacy relations on semigroups and monoids, focusing on the relation $a \cfn b$, defined by the existence of such that , , , an…
A new approach to the grammic monoid
Marianne Johnson, António Malheiro
We give an alternative description of the grammic monoid in terms of weakly increasing subsequences. Specifically, we show that words in the generators dete…
Structure of quasi-crystal graphs and applications to the combinatorics of quasi-symmetric functions
Alan J. Cain, António Malheiro, Fátima Rodrigues +1
Crystal graphs are powerful combinatorial tools for working with the plactic monoid and symmetric functions. Quasi-crystal graphs are an analogous concept for the hypoplactic monoi…