The $\mathrm{D}\mathrm{E}\mathrm{G}\mathrm{R}\mathrm{E}\mathrm{E}-\Delta$ CLOSEST PHYLOGENETIC $k\mathrm{T}\mathrm{H}$ Root PROBLEM $(\Delta \mathrm{C}\mathrm{P}\mathrm{R}k)$ is the problem ofâ€¦ (More)

We present an O(n)-time approximation algorithm for the maximum traveling salesman problem whose approximation ratio is asymptotically 61 81 , where n is the number of vertices in the input completeâ€¦ (More)

We present a cubic-time algorithm for the following problem: Given a simple graph, decide whether it is realized by adjacencies of countries in a map without holes, in which at most four countriesâ€¦ (More)

We consider a modified notion of planarity, in which two nations of a map are considered adjacent when they share any point of their boundaries (not necessarily an edge, as planarity requires). Suchâ€¦ (More)

The problem of computing a matching of maximum weight in a given edge-weighted graph is not known to be P-hard or in RNC. This paper presents four parallel approximation algorithms for this problem.â€¦ (More)