On the interval chromatic number of proper interval graphs
نویسندگان
چکیده
منابع مشابه
Induced Subgraph Isomorphism on Interval and Proper Interval Graphs
The Induced Subgraph Isomorphism problem on two input graphs G and H is to decide whether G has an induced subgraph isomorphic to H. Already for the restricted case where H is a complete graph the problem is NP-complete, as it is then equivalent to the Clique problem. In a recent paper [10] Marx and Schlotter show that Induced Subgraph Isomorphism is NP-complete when G and H are restricted to b...
متن کاملOn the chromatic number of multiple interval graphs and overlap graphs
Let x(G) and w(G) denote the chromatic number and clique number (maximum size of a clique) of a graph G. To avoid trivial cases, we always assume that w (G);?: 2. It is well known that interval graphs are perfect, in particular x( G)= w (G) for every interval graph G. In this paper we study the closeness of x and w for two well-known non-perfect relatives of interval graphs: multiple interval g...
متن کاملOn the interval number of special graphs
The interval number of a graph G is the least natural number t such that G is the intersection graph of sets, each of which is the union of at most t intervals, denoted by i (G ). Griggs and West showed that i(G) d12(d þ 1)e. We describe the extremal graphs for that inequality when d is even. For three special perfect graph classes we give bounds on the interval number in terms of the independe...
متن کاملA matrix characterization of interval and proper interval graphs
In this work a matrix representation that characterizes the interval and proper interval graphs is presented, which is useful for the efficient formulation and solution of optimization problems, such as the k-cluster problem. For the construction of this matrix representation every such graph is associated with a node versus node zero–one matrix. In contrast to representations used in most of t...
متن کاملBounded Representations of Interval and Proper Interval Graphs
Klav́ık et al. [arXiv:1207.6960] recently introduced a generalization of recognition called the bounded representation problem which we study for the classes of interval and proper interval graphs. The input gives a graph G and in addition for each vertex v two intervals Lv and Rv called bounds. We ask whether there exists a bounded representation in which each interval Iv has its left endpoint ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 2015
ISSN: 0012-365X
DOI: 10.1016/j.disc.2015.04.016