Bounds on the genus for 2-cell embeddings of prefix-reversal graphs

Fuente: arXiv
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Main Authors: Blanco, Saúl A., Buehrle, Charles
Format: Preprint
Published: 2023
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author Blanco, Saúl A.
Buehrle, Charles
author_facet Blanco, Saúl A.
Buehrle, Charles
contents In this paper, we provide bounds for the genus of the pancake graph $\mathbb{P}_n$, burnt pancake graph $\mathbb{BP}_n$, and undirected generalized pancake graph $\mathbb{P}_m(n)$. Our upper bound for $\mathbb{P}_n$ is sharper than the previously-known bound, and the other bounds presented are the first of their kind. Our proofs are constructive and rely on finding an appropriate rotation system (also referred to in the literature as Edmonds' permutation technique) where certain cycles in the graphs we consider become boundaries of regions of a 2-cell embedding. A key ingredient in the proof of our bounds for the genus $\mathbb{P}_n$ and $\mathbb{BP}_n$ is a labeling algorithm of their vertices that allows us to implement rotation systems to bound the number of regions of a 2-cell embedding of said graphs. All of our bounds are asymptotically tight; in particular, the genus of $\mathbb{P}_m(n)$ is $Θ(m^nnn!)$ for all $m\geq1$ and $n\geq2$.
format Preprint
id arxiv_https___arxiv_org_abs_2306_11295
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Bounds on the genus for 2-cell embeddings of prefix-reversal graphs
Blanco, Saúl A.
Buehrle, Charles
Combinatorics
Discrete Mathematics
05C38, 05C30
G.2.1; G.2.2
In this paper, we provide bounds for the genus of the pancake graph $\mathbb{P}_n$, burnt pancake graph $\mathbb{BP}_n$, and undirected generalized pancake graph $\mathbb{P}_m(n)$. Our upper bound for $\mathbb{P}_n$ is sharper than the previously-known bound, and the other bounds presented are the first of their kind. Our proofs are constructive and rely on finding an appropriate rotation system (also referred to in the literature as Edmonds' permutation technique) where certain cycles in the graphs we consider become boundaries of regions of a 2-cell embedding. A key ingredient in the proof of our bounds for the genus $\mathbb{P}_n$ and $\mathbb{BP}_n$ is a labeling algorithm of their vertices that allows us to implement rotation systems to bound the number of regions of a 2-cell embedding of said graphs. All of our bounds are asymptotically tight; in particular, the genus of $\mathbb{P}_m(n)$ is $Θ(m^nnn!)$ for all $m\geq1$ and $n\geq2$.
title Bounds on the genus for 2-cell embeddings of prefix-reversal graphs
topic Combinatorics
Discrete Mathematics
05C38, 05C30
G.2.1; G.2.2
url https://arxiv.org/abs/2306.11295