Unbent Collections of Orthogonal Drawings

Fuente: arXiv
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Main Authors: Antić, Todor, Liotta, Giuseppe, Masařík, Tomáš, Ortali, Giacomo, Pfretzschner, Matthias, Stumpf, Peter, Wolff, Alexander, Zink, Johannes
Format: Preprint
Published: 2025
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_version_ 1866910050948218880
author Antić, Todor
Liotta, Giuseppe
Masařík, Tomáš
Ortali, Giacomo
Pfretzschner, Matthias
Stumpf, Peter
Wolff, Alexander
Zink, Johannes
author_facet Antić, Todor
Liotta, Giuseppe
Masařík, Tomáš
Ortali, Giacomo
Pfretzschner, Matthias
Stumpf, Peter
Wolff, Alexander
Zink, Johannes
contents Recently, there has been interest in representing single graphs by multiple drawings; for example, using graph stories, storyplans, or uncrossed collections. In this paper, we apply this idea to orthogonal graph drawing. Due to the orthogonal drawing style, we focus on 4-graphs, that is, graphs of maximum degree 4. We restrict ourselves to plane graphs, that is, planar graphs whose embedding is fixed. Our goal is to represent any plane 4-graph $G$ by an unbent collection, that is, a collection of orthogonal drawings of $G$ that adhere to the embedding of $G$ and ensure that each edge of $G$ is drawn without bends in at least one of the drawings. We investigate two objectives. First, we consider minimizing the number of drawings in an unbent collection. We prove that every plane 4-graph can be represented by a collection with at most three drawings, which is tight. We also give necessary and sufficient conditions for a graph to admit an unbent collection of size $2$. Second, we consider minimizing the total number of bends over all drawings in an unbent collection. We show that this problem is NP-hard and give a 3-approximation algorithm. For the special case of plane triconnected cubic graphs, we show how to compute minimum-bend collections in linear time.
format Preprint
id arxiv_https___arxiv_org_abs_2502_18390
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Unbent Collections of Orthogonal Drawings
Antić, Todor
Liotta, Giuseppe
Masařík, Tomáš
Ortali, Giacomo
Pfretzschner, Matthias
Stumpf, Peter
Wolff, Alexander
Zink, Johannes
Computational Geometry
Discrete Mathematics
Data Structures and Algorithms
Combinatorics
68R10
Recently, there has been interest in representing single graphs by multiple drawings; for example, using graph stories, storyplans, or uncrossed collections. In this paper, we apply this idea to orthogonal graph drawing. Due to the orthogonal drawing style, we focus on 4-graphs, that is, graphs of maximum degree 4. We restrict ourselves to plane graphs, that is, planar graphs whose embedding is fixed. Our goal is to represent any plane 4-graph $G$ by an unbent collection, that is, a collection of orthogonal drawings of $G$ that adhere to the embedding of $G$ and ensure that each edge of $G$ is drawn without bends in at least one of the drawings. We investigate two objectives. First, we consider minimizing the number of drawings in an unbent collection. We prove that every plane 4-graph can be represented by a collection with at most three drawings, which is tight. We also give necessary and sufficient conditions for a graph to admit an unbent collection of size $2$. Second, we consider minimizing the total number of bends over all drawings in an unbent collection. We show that this problem is NP-hard and give a 3-approximation algorithm. For the special case of plane triconnected cubic graphs, we show how to compute minimum-bend collections in linear time.
title Unbent Collections of Orthogonal Drawings
topic Computational Geometry
Discrete Mathematics
Data Structures and Algorithms
Combinatorics
68R10
url https://arxiv.org/abs/2502.18390