Results 21 to 30 of about 975,712 (248)

An SPQR-tree-like embedding representation for level planarity

open access: yesJournal of Computational Geometry, 2023
An SPQR-tree is a data structure that efficiently represents all planar embeddings of a  connected planar graph. It is a key tool in a number of constrained planarity testing algorithms, which seek a planar embedding of a graph subject to some given set
Guido Brückner, Ignaz Rutter
doaj   +1 more source

Drawing planar graphs with many collinear vertices

open access: yesJournal of Computational Geometry, 2018
Consider the following problem: Given a planar graph $G$, what is the maximum number $p$ such that $G$ has a planar straight-line drawing with $p$ collinear vertices?
Giordano Da Lozzo   +4 more
doaj   +1 more source

Untangling a Planar Graph [PDF]

open access: yesDiscrete & Computational Geometry, 2008
A straight-line drawing $δ$ of a planar graph $G$ need not be plane, but can be made so by \emph{untangling} it, that is, by moving some of the vertices of $G$. Let shift$(G,δ)$ denote the minimum number of vertices that need to be moved to untangle $δ$. We show that shift$(G,δ)$ is NP-hard to compute and to approximate.
Xavier Goaoc   +5 more
openaire   +3 more sources

Total Semirelib Graph [PDF]

open access: yes, 2013
In this paper, the concept of Total semirelib graph of a planar graph is introduced. Authors present a characterization of those graphs whose total semirelib graphs are planar, outer planar, Eulerian, hamiltonian with crossing number ...
Prasad, Manjunath   +3 more
core   +1 more source

Matched Drawings of Planar Graphs

open access: yesJournal of Graph Algorithms and Applications, 2009
A natural way to draw two planar graphs whose vertex sets are matched is to assign each matched pair a unique y-coordinate. In this paper we introduce the concept of such matched drawings, which is a relaxation of simultaneous geometric embeddings with ...
Emilio Di Giacomo   +4 more
doaj   +1 more source

Minimizing the oriented diameter of a planar graph [PDF]

open access: yes, 2009
We consider the problem of minimizing the diameter of an orientation of a planar graph. A result of Chvátal and Thomassen shows that for general graphs, it is NP-complete to decide whether a graph can be oriented so that its diameter is at most two.
Noble, SD   +3 more
core   +1 more source

Improved Bounds for Track Numbers of Planar Graphs

open access: yesJournal of Graph Algorithms and Applications, 2020
A track layout of a graph consists of a vertex coloring and a total order of each color class, such that no two edges cross between any two color classes.
Sergey Pupyrev
doaj   +1 more source

The Liouville and the intersection properties are equivalent for planar graphs [PDF]

open access: yes, 2012
It is shown that if a planar graph admits no non-constant bounded harmonic function then the trajectories of two independent simple random walks intersect almost ...
Itai Benjamini   +5 more
core   +1 more source

Box-Rectangular Drawings of Planar Graphs

open access: yesJournal of Graph Algorithms and Applications, 2013
A plane graph is a planar graph with a fixed planar embedding in the plane. In a box- rectangular drawing of a plane graph, every vertex is drawn as a rectangle, called a box, each edge is drawn as either a horizontal line segment or a vertical line ...
Md. Manzurul Hasan   +2 more
doaj   +1 more source

NIC-planar graphs

open access: yesDiscrete Applied Mathematics, 2017
A graph is NIC-planar if it admits a drawing in the plane with at most one crossing per edge and such that two pairs of crossing edges share at most one common end vertex. NIC-planarity generalizes IC-planarity, which allows a vertex to be incident to at most one crossing edge, and specializes 1-planarity, which only requires at most one crossing per ...
Christian Bachmaier   +4 more
openaire   +3 more sources

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