منابع مشابه
Precoloring extension. I. Interval graphs
of the following general problem on vertex colorings of graphs. Suppose that some vertices of a graph G are assigned to some colors. Can this precoloring be extended to a proper coloring of G with at most k colors (for some given k)? This question was motivated by practical problems in scheduling and VLSI theory. Here we investigate its complexity status for interval graphs and for graphs wit...
متن کاملPrecoloring extension on unit interval graphs
In the precoloring extension problem we are given a graph with some of the vertices having a preassigned color and it has to be decided whether this coloring can be extended to a proper k-coloring of the graph. Answering an open question of Hujter and Tuza [6], we show that the precoloring extension problem is NP-complete on unit interval graphs.
متن کاملPrecoloring extension on chordal graphs
In the precoloring extension problem (PrExt) we are given a graph with some of the vertices having a preassigned color and it has to be decided whether this coloring can be extended to a proper k-coloring of the graph. 1-PrExt is the special case where every color is assigned to at most one vertex in the precoloring. Answering an open question of Hujter and Tuza [HT96], we show that the 1-PrExt...
متن کاملList precoloring extension in planar graphs
A celebrated result of Thomassen states that not only can every planar graph be colored properly with five colors, but no matter how arbitrary palettes of five colors are assigned to vertices, one can choose a color from the corresponding palette for each vertex so that the resulting coloring is proper. This result is referred to as 5-choosability of planar graphs. Albertson asked whether Thoma...
متن کاملPrecoloring extension for K4-minor-free graphs
Let G = (V, E) be a graph where every vertex v ∈ V is assigned a list of available colors L(v). We say that G is list colorable for a given list assignment if we can color every vertex using its list such that adjacent vertices get different colors. If L(v) = {1, . . . , k} for all v ∈ V then a corresponding list coloring is nothing other than an ordinary k-coloring of G. Assume that W ⊆ V is a...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1992
ISSN: 0012-365X
DOI: 10.1016/0012-365x(92)90646-w