Let G be a directed edge-weighted graph and let P be a shortest path from s to t in G. The replacement paths problem asks to compute, for every edge e on P, the shortest s-to-t pat...
Let S be a set of n points in IRd and let t > 1 be a real number. A t-spanner for S is a directed graph having the points of S as its vertices, such that for any pair p and q o...
We study problems of reconguration of shortest paths in graphs. We prove that the shortest reconguration sequence can be exponential in the size of the graph and that it is NP-hard...
We consider the problem of finding a k-edge transversal set that covers all (simple) cycles of length at most s in a planar graph, where s ≥ 3 is a constant. This problem, refe...
We show that the reachability problem for directed graphs that are either K3,3-free or K5-free is in unambiguous log-space, UL coUL. This significantly extends the result of Bour...