Strongly connected spanning subgraph for almost symmetric networks

A. Karim Abu-Affash, Paz Carmi, Anat Parush Tzur

Research output: Contribution to conferencePaperpeer-review


In the strongly connected spanning subgraph (SCSS) problem, the goal is to find a minimum weight spanning subgraph of a strongly connected directed graph that maintains the strong connectivity. In this paper, we consider the SCSS problem for two families of geometric directed graphs; t-spanners and symmetric disk graphs. Given a constant t ≥ 1, a directed graph G is a t-spanner of a set of points V if, for every two points u and v in V , there exists a directed path from u to v in G of length at most t |uv|, where |uv| is the Euclidean distance between u and v. Given a set V of points in the plane such that each point u ϵ V has a radius ru, the symmetric disk graph of V is a directed graph G = (V,E), such that E = {(u, v) : |uv| ≤ ru and |uv| ≤ rv}. Thus, if there exists a directed edge (u, v), then (v, u) exists as well. We present 3 4 (t+1) and 3 2 approximation algorithms for the SCSS problem for t-spanners and for symmetric disk graphs, respectively. Actually, our approach achieves a 3 4 (t + 1)-approximation algorithm for all directed graphs satisfying the property that, for every two nodes u and v, the ratio between the shortest paths, from u to v and from v to u in the graph, is at most t.

Original languageEnglish
Number of pages6
StatePublished - 1 Jan 2015
Event27th Canadian Conference on Computational Geometry, CCCG 2015 - Kingston, Canada
Duration: 10 Aug 201512 Aug 2015


Conference27th Canadian Conference on Computational Geometry, CCCG 2015

ASJC Scopus subject areas

  • Geometry and Topology
  • Computational Mathematics


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