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Box-threshold graphs

โœ Scribed by Uri N. Peled; Bruno Simeone


Publisher
John Wiley and Sons
Year
1984
Tongue
English
Weight
608 KB
Volume
8
Category
Article
ISSN
0364-9024

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โœฆ Synopsis


A graph is called box-threshold when all pairs of vertices with incomparable neighborhoods have the same degree. Several properties of box-threshold graphs, generalizing properties of threshold graphs, are proved. A transportation model with priority constraints is used to characterize their degree sequences. Further characterizations are given using the concept of the frame of a graph.

1. Introduction

We consider finite undirected loopless graphs without multiple edges, except that loops will be used in Section 4. For graph G(V,E), the vicinal preorder 3 on V is defined by

That is, x a y if and only if every neighbor of y is a neighbor of x or x itself.

Graph G is a threshold graph when its vicinal preorder is a total (linear)

order. This means that there do not exist incomparable vertices, i.e.,


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