Periodic Infinite Frieze Patterns of Type ${\Lambda }_{p_1,\dots ,p_n}$ and Dissections on Annuli

Abstract

Finite frieze patterns with entries in $\mathbb{Z}[{\lambda }_{p_1},\dots ,{\lambda }_{p_s}]$ where $\{p_1,\dots ,p_s\}\subseteq {\mathbb{Z}}_{\ge 3}$ and ${\lambda }_p=2\cos (\pi /p)$ were shown to have a connection to dissected polygons by Holm and Jorgensen. We extend their work by studying the connection between infinite frieze patterns with such entries and dissections of annuli and once-punctured discs. We give an algorithm to determine whether a frieze pattern with entries in $\mathbb{Z}[{\lambda }_{p_1},\dots ,{\lambda }_{p_s}]$, finite or infinite, comes from a dissected surface. We introduce quotient dissections as a realization for some frieze patterns unrealizable by an ordinary dissection. We also introduce two combinatorial interpretations for entries of frieze patterns from dissected surfaces. These interpretations are a generalization of matchings introduced by Broline, Crowe, and Isaacs for finite frieze patterns over $\mathbb{Z}$.

arXiv comment52 pages, many figures, comments welcome