Train Tracks and Confluent Drawings

  • Authors:
  • Peter Hui;Michael J. Pelsmajer;Marcus Schaefer;Daniel Stefankovic

  • Affiliations:
  • Department of Computer Science, DePaul University, Chicago, IL 60604, USA;Department of Applied Mathematics, Illinois Institute of Technology, Chicago, IL 60616, USA;Department of Computer Science, DePaul University, Chicago, IL 60604, USA;Computer Science Department, University of Rochester, Rochester, NY 14627-0226, USA

  • Venue:
  • Algorithmica
  • Year:
  • 2007

Quantified Score

Hi-index 0.00

Visualization

Abstract

Confluent graphs capture the connection properties of train tracks, offering a very natural generalization of planar graphs, and—as the example of railroad maps shows—are an important tool in graph visualization. In this paper we continue the study of confluent graphs, introducing strongly confluent graphs and tree-confluent graphs. We show that strongly confluent graphs can be recognized in NP (the complexity of recognizing confluent graphs remains open). We also give a natural elimination ordering characterization of tree-confluent graphs, and we show that this class coincides with the (6,2)-chordal bipartite graphs. Finally, we define outerconfluent graphs and identify the bipartite permutation graphs as a natural subclass.