Visibility Representations of Four-Connected Plane Graphs with Near Optimal Heights
نویسندگان
چکیده
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 ⌉ + 2 ⌈√ n−2 2 ⌉ . 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 n2 .
منابع مشابه
Simultaneous Visibility Representations of Plane st-graphs Using L-shapes
Let 〈Gr, Gb〉 be a pair of plane st-graphs with the same vertex set V . A simultaneous visibility representation with L-shapes of 〈Gr, Gb〉 is a pair of bar visibility representations 〈Γr, Γb〉 such that, for every vertex v ∈ V , Γr(v) and Γb(v) are a horizontal and a vertical segment, which share an end-point. In other words, every vertex is drawn as an L-shape, every edge of Gr is a vertical vis...
متن کاملGraphs with Plane Outside-Obstacle Representations
An obstacle representation of a graph consists of a set of polygonal obstacles and a distinct point for each vertex such that two points see each other if and only if the corresponding vertices are adjacent. Obstacle representations are a recent generalization of classical polygon–vertex visibility graphs, for which the characterization and recognition problems are long-standing open questions....
متن کاملRectangle-Visibility Representations of Bipartite Graphs
The paper considers representations of bipartite graphs as rectangle-visibility graphs, Le., graphs whose vertices are rectangles in the plane, with adjacency detenmned by horizontal and vertical visibility.1t is shown that, for p ~ q, Kp,q has a representation with no rectangles having collinear sides if and only if p ~ 2 or p = 3 and q ~ 4. More generally, it is shown that Kp;q is a rectangle...
متن کاملRepresentations of Graphs on a Cylinder
A complete characterization of the class of graphs that admit a cylindric visibility representation is presented, where vertices are represented by intervals parallel to the axis ofthe cylinder and the edges correspond to pairs of visible intervals. Moreover, linear time algorithms are given for testing the existence of and constructing such a representation. Important applications of cylindric...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Comput. Geom.
دوره 42 شماره
صفحات -
تاریخ انتشار 2008