For a given node t in a directed graph G(VG, EG) and a positive integer k we study the problem of computing a set of k new links pointing to t – so called backlinks to t – prod...
Consider a randomly oriented graph G = (V, E) and let a, s and b be three distinct vertices in V . We study the correlation between the events {a → s} and {s → b}. We show that...
Given a forest F = (V, E) and a positive integer D, we consider the problem of finding a minimum number of new edges E such that in the augmented graph H = (V, E∪E ) any pair of...
Let S be a set of n points in general position in the plane, labelled bijectively with the integers {0, 1, . . ., n - 1}. Each edge (the straight segment that joins two points) is...
Given a graph G = (V, E) and a positive integer k, the PARTITION INTO CLIQUES (PIC) decision problem consists of deciding whether there exists a partition of V into k disjoint sub...