Mihály Hujter

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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(More)
We continue the study 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)? Here we investigate the complexity status of precoloring extendibility on some classes of perfect(More)
For a natural number t , denote by N, the graph K2,\tK2, i.e. the graph obtained by deleting a perfect matching from the complete graph of order 2t. For example, NI is the edgeless graph on 2 vertices, N2 is the 4-cycle, and N3 is the octahedron graph shown in Fig. 1. The graphs N, were first studied by Neumann in 1942 (see [2, 61). We say that a graph G =(More)
In this note we investigate the computational complexity of the transportation problem with a permutable demand vector, TP-PD for short. In the TP-PD, the goal is to permute the elements of the given integer demand vector b ˆ …b1; . . . ; bn† in order to minimize the overall transportation costs. Meusel and Burkard [6] recently proved that the TP-PD is(More)
We continue the study 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)? Here we investigate the complexity status of precoloring extendibility on some graph classes which(More)