GD 2012: Graph Drawing pp 67-78

# Progress on Partial Edge Drawings

• Till Bruckdorfer
• Sabine Cornelsen
• Carsten Gutwenger
• Michael Kaufmann
• Fabrizio Montecchiani
• Martin Nöllenburg
• Alexander Wolff
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 7704)

## Abstract

Recently, a new way of avoiding crossings in straight-line drawings of non-planar graphs has been investigated. The idea of partial edge drawings (PED) is to drop the middle part of edges and rely on the remaining edge parts called stubs. We focus on a symmetric model (SPED) that requires the two stubs of an edge to be of equal length. In this way, the stub at the other endpoint of an edge assures the viewer of the edge’s existence. We also consider an additional homogeneity constraint that forces the stub lengths to be a given fraction δ of the edge lengths (δ-SHPED). Given length and direction of a stub, this model helps to infer the position of the opposite stub.

We show that, for a fixed stub–edge length ratio δ, not all graphs have a δ-SHPED. Specifically, we show that K241 does not have a 1/4-SHPED, while bandwidth-k graphs always have a $$\Theta(1/\sqrt{k})$$-SHPED. We also give bounds for complete bipartite graphs. Further, we consider the problem MaxSPED where the task is to compute the SPED of maximum total stub length that a given straight-line drawing contains. We present an efficient solution for 2-planar drawings and a 2-approximation algorithm for the dual problem.

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## Authors and Affiliations

• Till Bruckdorfer
• 1
• Sabine Cornelsen
• 2
• Carsten Gutwenger
• 3
• Michael Kaufmann
• 1
• Fabrizio Montecchiani
• 4
• Martin Nöllenburg
• 5
• Alexander Wolff
• 6
1. 1.Universität TübingenGermany
2. 2.Universität KonstanzGermany
3. 3.Universität DortmundGermany
4. 4.Università degli Studi di PerugiaItaly
5. 5.Institut für Theoretische InformatikKITGermany
6. 6.Lehrstuhl für Informatik IUniversität WürzburgGermany