Visibility Representations of Four-Connected Plane Graphs with Near Optimal Heights

碩士 === 國立臺灣大學 === 資訊網路與多媒體研究所 === 96 === A visibility representation of a graph G is to represent the nodes of G with non-overlapping horizontal line segments such that the line segments representing any two distinct adjacent nodes are vertically visible to each other. If G is a plane graph, i.e., a...

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Bibliographic Details
Main Authors: Ya-Fei Hung, 洪雅斐
Other Authors: Hsueh-I Lu
Format: Others
Language:en_US
Published: 2008
Online Access:http://ndltd.ncl.edu.tw/handle/77777426186889590325
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Summary:碩士 === 國立臺灣大學 === 資訊網路與多媒體研究所 === 96 === A visibility representation of a graph G is to represent the nodes of G with non-overlapping horizontal line segments such that the line segments representing any two distinct adjacent nodes are vertically visible to each other. If G is a plane graph, i.e., a planar graph equipped with a planar embedding, a visibility representation of G has the additional requirement of reflecting the given planar embedding of G. For the case that G is an n-node four-connected plane graph, we give an O(n)-time algorithm to produce a visibility representation of G with height at most n/2+ O(sqrt(n)). To ensure that the first-order term of the upper bound is optimal, we also show an n-node four-connected plane graph G, for infinite number of n, whose visibility representations require heights at least n/2.