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arXiv · 1708.09107

Planar L-Drawings of Directed Graphs

Steven Chaplick·Markus Chimani·Sabine Cornelsen·Giordano Da Lozzo·Martin Nöllenburg·Maurizio Patrignani·Ioannis G. Tollis·Alexander Wolff
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Abstract

We study planar drawings of directed graphs in the L-drawing standard. We provide necessary conditions for the existence of these drawings and show that testing for the existence of a planar L-drawing is an NP-complete problem. Motivated by this result, we focus on upward-planar L-drawings. We show that directed st-graphs admitting an upward- (resp. upward-rightward-) planar L-drawing are exactly those admitting a bitonic (resp. monotonically increasing) st-ordering. We give a linear-time algorithm that computes a bitonic (resp. monotonically increasing) st-ordering of a planar st-graph or reports that there exists none.

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Steven Chaplick, Markus Chimani, Sabine Cornelsen, Giordano Da Lozzo, Martin Nöllenburg, Maurizio Patrignani, Ioannis G. Tollis, Alexander Wolff. 2017-09-01. Planar L-Drawings of Directed Graphs. https://arxiv.org/abs/1708.09107

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