منابع مشابه
First-fit coloring on interval graphs has performance ratio at least 5
First-fit is the online graph coloring algorithm that considers vertices one at a time in some order and assigns each vertex the least positive integer not used already on a neighbor. The maximum number of colors used by first-fit on graph G over all vertex orders is denoted χFF (G). The exact value of R := supG χFF (G) ω(G) over interval graphs G is unknown. Pemmaraju, Raman, and Varadarajan (...
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In this paper, we study the sub-coloring and hypo-coloring problems on interval graphs. These problems have applications in job scheduling and distributed computing and can be used as “subroutines” for other combinatorial optimization problems. In the sub-coloring problem, given a graph G, we want to partition the vertices of G into minimum number of sub-color classes, where each sub-color clas...
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Given a graph G with nonnegative node labels w, a multiset of stable sets S1, . . . , Sk ⊆ V (G) such that each vertex v ∈ V (G) is contained in w(v) many of these stable sets is called a weighted coloring. The weighted coloring number χw(G) is the smallest k such that there exist stable sets as above. We provide a polynomial time combinatorial algorithm that computes the weighted coloring numb...
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We study the problem of online coloring co-interval graphs. In this problem, a set of intervals on the real line is presented to the online algorithm in some arbitrary order, and the algorithm must assign each interval a color that is different from the colors of all previously presented intervals not intersecting the current interval. It is known that the competitive ratio of the simple First-...
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We study the performance of the algorithms First-Fit and Next-Fit for two online edge coloring problems. In the min-coloring problem, all edges must be colored using as few colors as possible. In the max-coloring problem, a fixed number of colors is given, and as many edges as possible should be colored. Previous analysis using the competitive ratio has not separated the performance of First-Fi...
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ژورنال
عنوان ژورنال: Discrete Mathematics
سال: 1995
ISSN: 0012-365X
DOI: 10.1016/0012-365x(94)00285-q