Title
Interval k-Graphs and Orders.
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.
Year
DOI
Venue
2018
10.1007/s11083-017-9445-0
ORDER-A JOURNAL ON THE THEORY OF ORDERED SETS AND ITS APPLICATIONS
Keywords
Field
DocType
Interval graphs,Interval orders,Interval k-graphs,Forbidden subgraph characterization
Discrete mathematics,Combinatorics,Interval order,Interval graph,Vertex (geometry),Real line,Intersection graph,If and only if,Conjecture,Mathematics,The Intersect
Journal
Volume
Issue
ISSN
35.0
3
0167-8094
Citations 
PageRank 
References 
0
0.34
6
Authors
3
Name
Order
Citations
PageRank
David E. Brown1152.74
Breeann Flesch200.68
Larry J. Langley3145.19