The lexicographic kernel of a game lexicographically maximizes the surplusses s <Subscript> ij </Subscript> (rather than the excesses as would the nucleolus) and is contained in both the least core and the kernel. We show that an element in the lexicographic kernel can be computed efficiently, provided we can...</subscript>

Various least core concepts including the classical least core of cooperative games are discussed. By a reduction from minimum cover problems, we prove that computing an element in these least cores is in general NP-hard for minimum cost spanning tree games. As a consequence, computing the...

The Dreyfus–Wagner algorithm is a well-known dynamic programming method for computing minimum Steiner trees in general weighted graphs in time O <Superscript>*</Superscript>(3<Superscript> k </Superscript>), where k is the number of terminal nodes to be connected. We improve its running time to O <Superscript>*</Superscript>(2.684<Superscript> k </Superscript>) by showing that the optimum Steiner...</superscript></superscript></superscript></superscript>