Commuting Upper Triangular Binary Morphisms

Issue title: Codes, Graphs, Coverings, and Identification: Special Issue Honoring the 60-th Birthday of Professor Iiro Honkala

Guest editors: Vesa Halava, Jarkko Kari and Tero Laihonen

Article type: Research Article

Authors: Honkala, Juha^{; *}

Affiliations: Department of Mathematics and Statistics, University of Turku, FI-20014 Turku, Finland. [email protected]

Correspondence: [*] Address for correspondence: Department of Mathematics and Statistics, University of Turku, FI-20014 Turku, Finland.

Abstract: A morphism g from the free monoid X* into itself is called upper triangular if the matrix of g is upper triangular. We characterize all upper triangular binary morphisms g1 and g2 such that g1g2 = g2g1.

Keywords: Free monoid morphism, Commutativity, Combinatorics on morphisms

DOI: 10.3233/FI-242183

Journal: Fundamenta Informaticae, vol. 191, no. 3-4, pp. 285-298, 2024