The Undirected Optical Indices of Trees

Fuente: arXiv
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Autores principales: Lo, Yuan-Hsun, Fu, Hung-Lin, Zhang, Yijin, Wong, Wing Shing
Formato: Preprint
Publicado: 2018
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author Lo, Yuan-Hsun
Fu, Hung-Lin
Zhang, Yijin
Wong, Wing Shing
author_facet Lo, Yuan-Hsun
Fu, Hung-Lin
Zhang, Yijin
Wong, Wing Shing
contents For a connected graph $G$, an instance $I$ is a set of pairs of vertices and a corresponding routing $R$ is a set of paths specified for all vertex-pairs in $I$. Let $\mathfrak{R}_I$ be the collection of all routings with respect to $I$. The undirected optical index of $G$ with respect to $I$ refers to the minimum integer $k$ to guarantee the existence of a mapping $ϕ:R\to\{1,2,\ldots,k\}$, such that $ϕ(P)\neqϕ(P')$ if $P$ and $P'$ have common edge(s), over all routings $R\in\mathfrak{R}_I$. A natural lower bound of the undirected optical index is the edge-forwarding index, which is defined to be the minimum of the maximum edge-load over all possible routings. Let $w(G,I)$ and $π(G,I)$ denote the undirected optical index and edge-forwarding index with respect to $I$, respectively. In this paper, we derive the inequality $w(T,I_A)<\frac{3}{2}π(T,I_A)$ for any tree $T$, where $I_A:=\{\{x,y\}:\,x,y\in V(T)\}$ is the all-to-all instance.
format Preprint
id arxiv_https___arxiv_org_abs_1808_09256
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle The Undirected Optical Indices of Trees
Lo, Yuan-Hsun
Fu, Hung-Lin
Zhang, Yijin
Wong, Wing Shing
Combinatorics
05C05, 05C15, 05C90
For a connected graph $G$, an instance $I$ is a set of pairs of vertices and a corresponding routing $R$ is a set of paths specified for all vertex-pairs in $I$. Let $\mathfrak{R}_I$ be the collection of all routings with respect to $I$. The undirected optical index of $G$ with respect to $I$ refers to the minimum integer $k$ to guarantee the existence of a mapping $ϕ:R\to\{1,2,\ldots,k\}$, such that $ϕ(P)\neqϕ(P')$ if $P$ and $P'$ have common edge(s), over all routings $R\in\mathfrak{R}_I$. A natural lower bound of the undirected optical index is the edge-forwarding index, which is defined to be the minimum of the maximum edge-load over all possible routings. Let $w(G,I)$ and $π(G,I)$ denote the undirected optical index and edge-forwarding index with respect to $I$, respectively. In this paper, we derive the inequality $w(T,I_A)<\frac{3}{2}π(T,I_A)$ for any tree $T$, where $I_A:=\{\{x,y\}:\,x,y\in V(T)\}$ is the all-to-all instance.
title The Undirected Optical Indices of Trees
topic Combinatorics
05C05, 05C15, 05C90
url https://arxiv.org/abs/1808.09256