Abstract
An interval k-graph is the intersection graph of a family of intervals of the real line partitioned into k classes with vertices adjacent if and only if their corresponding intervals intersect and belong to different classes. In this paper we study the cocomparability interval k-graphs; that is, the interval k-graphs whose complements have a transitive orientation and are therefore the incomparability graphs of strict partial orders. For brevity we call these orders interval k-orders. We characterize the kind of interval representations a cocomparability interval k-graph must have, and identify the structure that guarantees an order is an interval k-order. The case k = 2 is peculiar: cocomparability interval 2-graphs (equivalently proper- or unit-interval bigraphs, bipartite permutation graphs, and complements of proper circular-arc graphs to name a few) have been characterized in many ways, but we show that analogous characterizations do not hold if k > 2. We characterize the cocomparability interval 3-graphs via one forbidden subgraph and hence interval 3-orders via one forbidden suborder.
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References
Brandstädt, A., Spinrad, J., Stewart, L.: Bipartite permutation graphs. Discret. Appl. Math. 18, 279–292 (1987)
Brown, D.E., Flesch, B.M.: A characterization of 2-tree proper interval 3-graphs. J. Discret. Math. 2014, 143809 (2014). https://doi.org/10.1155/2014/143809
Brown, D.E., Langley, L.J.: The Mathematics Of Preference, Choice and Order: Essays in Honor of Peter C. Fishburn, ch. Probe Interval Orders, pp 313–322. Springer, Heidelberg (2009)
Brown, D.E.: Variations on Interval Graphs. Ph.D. thesis, University of Colorado Denver (2004)
Brown, D.E., Lundgren, J.R.: Bipartite probe interval graphs, interval point bigraphs, and circular arc graphs. Aust. J. Commun. 35, 221–236 (2006)
Brown, D.E., Lundgren, J.R.: Characterizations for unit interval bigraphs. Congr. Numer. 206, 5–17 (2010)
Brown, D.E., Lundgren, J.R., Sheng, L.: Cycle-free unit and proper probe interval graphs, submitted to Discret. Appl. Math.
Corneil, D.G., Olariu, S., Stewart, L.: Asteroidal triple-free graphs. SIAM J. Discrete Math. 10, 399–430 (1997)
Das, S., Roy, A.B., Sen, M., West, D.B.: Interval digraphs: an analogue of interval graphs. Journal of Graph Theory 13(2), 189–202 (1989)
Dilworth, R.P.: A decomposition theorem for partially ordered sets. Ann. Math. 51, 161–166 (1950)
Dushnik, B., Miller, E.W.: Partially ordered sets. Amer. J. Math. 63, 600–610 (1941). MR MR0004862 (3,73a)
Fulkerson, D.R., Gross, O.A.: Incidence matrices and interval graphs. Pac. J. Math. 15, 835–855 (1965)
Gallai, T.: Transitiv orientbare graphen. Acta Math. Acad. Sci. Hungar 18, 25–66 (1967)
Golumbic, M.C., Rotem, D., Urrutia, J.: Comparability graphs and intersection graphs. Discret. Math. 43, 37–46 (1983)
Hayward, R.B.: Weakly triangulated graphs. J. Comb. Theory (B) 39, 200–209 (1985)
Hell, P., Huang, J.: Interval bigraphs and circular arc graphs. J. Graph Theory 46, 313–327 (2004)
Hiraguchi, T.: On the dimension of orders. Sci. Reports Kanazawa Univ. 4(4), 1–20 (1955)
McKee, T., McMorris, F.R.: Topics in Intersection Graph Theory. Society for Industrial and Applied Mathematics, Philadelphia (1999)
McMorris, F.R., Wang, C., Zhang, P.: On probe interval graphs. Discret. Appl. Math. 88, 315–324 (1998)
Sanyal, B.K., Sen, M.K.: Indifference digraphs: a generalization of indifference graphs and semiorders. SIAM J. Discrete Math. 7(2), 157–165 (1994)
Sheng, L.: Cycle-free probe interval graphs. Congressus Numerantium 88, 33–42 (1999)
Spinrad, J.: Circular-arc graphs with clique cover number two. J. Comb. Theory, Series B 44(3), 300–306 (1987)
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Brown, D.E., Flesch, B.M. & Langley, L.J. Interval k-Graphs and Orders. Order 35, 495–514 (2018). https://doi.org/10.1007/s11083-017-9445-0
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DOI: https://doi.org/10.1007/s11083-017-9445-0