On Strict (Outer-)Confluent Graphs
Abstract
A strict confluent (SC) graph drawing is a drawing of a graph with vertices as points in the plane, where vertex adjacencies are represented not by individual curves but rather by unique smooth paths through a planar system of junctions and arcs. If all vertices of the graph lie in the outer face of the drawing, the drawing is called a strict outerconfluent (SOC) drawing. SC and SOC graphs were first considered by Eppstein et al. in Graph Drawing 2013. Here, we establish several new relationships between the class of SC graphs and other graph classes, in particular string graphs and unit-interval graphs. Further, we extend earlier results about special bipartite graph classes to the notion of strict outerconfluency, show that SOC graphs have cop number two, and establish that tree-like (\(\varDelta \)-)SOC graphs have bounded cliquewidth.
References
- 1.Aigner, M., Fromme, M.: A game of cops and robbers. Discrete Appl. Math. 8(1), 1–12 (1984). https://doi.org/10.1016/0166-218X(84)90073-8MathSciNetCrossRefzbMATHGoogle Scholar
- 2.Bach, B., Riche, N.H., Hurter, C., Marriott, K., Dwyer, T.: Towards unambiguous edge bundling: investigating confluent drawings for network visualization. IEEE Trans. Vis. Comput. Graph. 23(1), 541–550 (2017). https://doi.org/10.1109/TVCG.2016.2598958CrossRefGoogle Scholar
- 3.Baker, B.S.: Approximation algorithms for NP-complete problems on planar graphs. J. ACM 41(1), 153–180 (1994). https://doi.org/10.1145/174644.174650MathSciNetCrossRefzbMATHGoogle Scholar
- 4.Benzaken, C., Crama, Y., Duchet, P., Hammer, P.L., Maffray, F.: More characterizations of triangulated graphs. J. Graph Theory 14(4), 413–422 (1990). https://doi.org/10.1002/jgt.3190140404MathSciNetCrossRefzbMATHGoogle Scholar
- 5.Brandstädt, A., Spinrad, J., Stewart, L.: Bipartite permutation graphs are bipartite tolerance graphs. Congressus Numerantium 58, 165–174 (1987)MathSciNetzbMATHGoogle Scholar
- 6.Courcelle, B., Makowsky, J.A., Rotics, U.: Linear time solvable optimization problems on graphs of bounded clique-width. Theory Comput. Syst. 33(2), 125–150 (2000). https://doi.org/10.1007/s002249910009MathSciNetCrossRefzbMATHGoogle Scholar
- 7.Courcelle, B., Olariu, S.: Upper bounds to the clique width of graphs. Discrete Appl. Math. 101(1–3), 77–114 (2000). https://doi.org/10.1016/S0166-218X(99)00184-5MathSciNetCrossRefzbMATHGoogle Scholar
- 8.Dickerson, M., Eppstein, D., Goodrich, M.T., Meng, J.Y.: Confluent drawings: visualizing non-planar diagrams in a planar way. J. Graph Algorithms Appl. 9(1), 31–52 (2005). https://doi.org/10.7155/jgaa.00099MathSciNetCrossRefzbMATHGoogle Scholar
- 9.Ehrlich, G., Even, S., Tarjan, R.E.: Intersection graphs of curves in the plane. J. Comb. Theory Ser. B 21(1), 8–20 (1976). https://doi.org/10.1016/0095-8956(76)90022-8MathSciNetCrossRefzbMATHGoogle Scholar
- 10.Eppstein, D., Goodrich, M.T., Meng, J.Y.: Delta-confluent drawings. In: Healy, P., Nikolov, N.S. (eds.) GD 2005. LNCS, vol. 3843, pp. 165–176. Springer, Heidelberg (2006). https://doi.org/10.1007/11618058_16CrossRefGoogle Scholar
- 11.Eppstein, D., Goodrich, M.T., Meng, J.Y.: Confluent layered drawings. Algorithmica 47, 439–452 (2007). https://doi.org/10.1007/s00453-006-0159-8MathSciNetCrossRefzbMATHGoogle Scholar
- 12.Eppstein, D., Holten, D., Löffler, M., Nöllenburg, M., Speckmann, B., Verbeek, K.: Strict confluent drawing. J. Comput. Geom. 7(1), 22–46 (2016). https://doi.org/10.20382/jocg.v7i1a2MathSciNetCrossRefzbMATHGoogle Scholar
- 13.Eppstein, D., Simons, J.A.: Confluent Hasse diagrams. J. Graph Algorithms Appl. 17(7), 689–710 (2013). https://doi.org/10.1007/978-3-642-25878-7_2MathSciNetCrossRefzbMATHGoogle Scholar
- 14.Förster, H., Ganian, R., Klute, F., Nöllenburg, M.: On strict (outer-)confluent graphs. CoRR abs/1908.05345 (2019). http://arxiv.org/abs/1908.05345
- 15.Gabor, C.P., Supowit, K.J., Hsu, W.L.: Recognizing circle graphs in polynomial time. J. ACM 36(3), 435–473 (1989). https://doi.org/10.1145/65950.65951MathSciNetCrossRefzbMATHGoogle Scholar
- 16.Gavenčiak, T., Jelínek, V., Klavík, P., Kratochvíl, J.: Cops and robbers on intersection graphs. In: Cai, L., Cheng, S.-W., Lam, T.-W. (eds.) ISAAC 2013. LNCS, vol. 8283, pp. 174–184. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-45030-3_17, https://doi.org/10.1016/j.ejc.2018.04.009
- 17.Gavril, F.: Algorithms for minimum coloring, maximum clique, minimum covering by cliques, and maximum independent set of a chordal graph. SIAM J. Comput. 1(2), 180–187 (1972). https://doi.org/10.1137/0201013MathSciNetCrossRefzbMATHGoogle Scholar
- 18.Gavril, F.: Maximum weight independent sets and cliques in intersection graphs of filaments. Inf. Process. Lett. 73(5–6), 181–188 (2000). https://doi.org/10.1016/S0020-0190(00)00025-9MathSciNetCrossRefzbMATHGoogle Scholar
- 19.Gioan, E., Paul, C.: Split decomposition and graph-labelled trees: characterizations and fully dynamic algorithms for totally decomposable graphs. Discrete Appl. Math. 160(6), 708–733 (2012). https://doi.org/10.1016/j.dam.2011.05.007MathSciNetCrossRefzbMATHGoogle Scholar
- 20.Golumbic, M.C.: Algorithmic Graph Theory and Perfect Graphs, vol. 57. Elsevier, Amsterdam (2004). https://doi.org/10.1002/net.3230130214CrossRefzbMATHGoogle Scholar
- 21.Golumbic, M.C., Monma, C.L., Trotter Jr., W.T.: Tolerance graphs. Discrete Appl. Math. 9(2), 157–170 (1984). https://doi.org/10.1016/0166-218X(84)90016-7MathSciNetCrossRefzbMATHGoogle Scholar
- 22.Golumbic, M.C., Rotem, D., Urrutia, J.: Comparability graphs and intersection graphs. Discrete Math. 43(1), 37–46 (1983). https://doi.org/10.1016/0012-365X(83)90019-5MathSciNetCrossRefzbMATHGoogle Scholar
- 23.Golumbic, M.C., Rotics, U.: On the clique-width of some perfect graph classes. Int. J. Found. Comput. Sci. 11(3), 423–443 (2000). https://doi.org/10.1142/S0129054100000260MathSciNetCrossRefzbMATHGoogle Scholar
- 24.Halldórsson, M.M., Kitaev, S., Pyatkin, A.: Alternation graphs. In: Kolman, P., Kratochvíl, J. (eds.) WG 2011. LNCS, vol. 6986, pp. 191–202. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-25870-1_18CrossRefGoogle Scholar
- 25.Holten, D.: Hierarchical edge bundles: visualization of adjacency relations in hierarchical data. IEEE Trans. Vis. Comput. Graph. 12(5), 741–748 (2006). https://doi.org/10.1109/TVCG.2006.147CrossRefGoogle Scholar
- 26.Hsu, W.L.: Maximum weight clique algorithms for circular-arc graphs and circle graphs. SIAM J. Comput. 14(1), 224–231 (1985). https://doi.org/10.1137/0214018MathSciNetCrossRefzbMATHGoogle Scholar
- 27.Hui, P., Pelsmajer, M.J., Schaefer, M., Stefankovic, D.: Train tracks and confluent drawings. Algorithmica 47(4), 465–479 (2007). https://doi.org/10.1007/s00453-006-0165-xMathSciNetCrossRefzbMATHGoogle Scholar
- 28.Kratochvíl, J.: String graphs. I. The number of critical nonstring graphs is infinite. J. Comb. Theory Ser. B 52(1), 53–66 (1991). https://doi.org/10.1016/0095-8956(91)90090-7MathSciNetCrossRefzbMATHGoogle Scholar
- 29.Pnueli, A., Lempel, A., Even, S.: Transitive orientation of graphs and identification of permutation graphs. Can. J. Math. 23(1), 160–175 (1971). https://doi.org/10.4153/CJM-1971-016-5MathSciNetCrossRefzbMATHGoogle Scholar
- 30.Roberts, F.S.: Indifference graphs. In: Proof Techniques in Graph Theory, pp. 139–146 (1969)Google Scholar
- 31.Takamizawa, K., Nishizeki, T., Saito, N.: Linear-time computability of combinatorial problems on series-parallel graphs. J. ACM 29(3), 623–641 (1982). https://doi.org/10.1145/322326.322328MathSciNetCrossRefzbMATHGoogle Scholar
- 32.Trotter, W.T.: Combinatorics and Partially Ordered Sets: Dimension Theory, vol. 6. JHU Press, Baltimore (2001). https://doi.org/10.1137/1035116CrossRefzbMATHGoogle Scholar
- 33.Wegner, G.: Eigenschaften der Nerven homologisch-einfacher Familien im Rn. Ph.D. thesis, Universität Göttingen (1967)Google Scholar
- 34.Yu, C.W., Chen, G.H.: Efficient parallel algorithms for doubly convex-bipartite graphs. Theoret. Comput. Sci. 147(1–2), 249–265 (1995). https://doi.org/10.1016/0304-3975(94)00220-DMathSciNetCrossRefzbMATHGoogle Scholar